A high-entropy carbide-high-entropy carbonitride ceramic cutting tool and a preparation method and application thereof

Abstract

The application belongs to the field of ceramic cutters, and discloses a high-entropy carbide-high-entropy carbonitride ceramic cutter and a preparation method and application thereof. The ceramic cutter comprises a cutter tip high-entropy carbide (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C and a relief high-entropy carbonitride (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C x N 1‑x (0.1≤x≤0.9). The carbide mixed powder of TiC, ZrC, NbC, TaC and WC and the carbonitride mixed powder of TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and Ni powder are sintered by discharge plasma under vacuum environment at a pressure of 30-50 MPa and at a temperature of 1600-1800 DEG C. The cutter tip of the ceramic cutter has high hardness, the relief has high toughness and wear resistance, and the ceramic cutter can be applied to continuous cutting of high-hardness materials.

Description

Technical Field

[0001] This invention belongs to the field of ceramic cutting tool technology, and more specifically, relates to a high-entropy carbide knife—a high-entropy carbonitride ceramic cutting tool, its preparation method, and its application. Background Technology

[0002] High-entropy ceramics are a novel materials design theory that has emerged in recent years and are currently a hot topic in materials research. The concept originated from high-entropy alloys. High-entropy ceramics are generally multi-component single-phase solid solutions composed of four or more cations in equal or near-equal amounts. Due to their unique "high-entropy effect," high-entropy ceramics exhibit higher strength, hardness, excellent wear resistance, excellent high-temperature strength, good structural stability, and good corrosion resistance and oxidation resistance compared to their constituent single-phase components. The increased number of components significantly expands the combinatorial space for exploring and discovering new materials. In high-entropy ceramics, the increased configurational entropy of the ceramic system due to the increased components leads to a decrease in its Gibbs free energy, making the ceramic system more stable and exhibiting excellent stability. Furthermore, because various atoms are randomly distributed in the crystal lattice, the environment and occupancy of each atom are different, resulting in more lattice distortions and defects within the crystal, making slip difficult and improving performance.

[0003] High-entropy carbide materials possess excellent mechanical properties, making them suitable for cutting tool applications. However, due to their low toughness, they experience rapid flank wear during turning. In contrast, the introduction of nitrogen into high-entropy carbonitride materials increases the material's configurational entropy and the stability of the high-entropy system, thereby enhancing toughness and providing better wear resistance. Combining the superior properties of these two high-entropy materials could potentially enable high-entropy ceramic cutting tools to achieve high-speed, long-life cutting of materials with high hardness, high cutting temperatures, and a tendency to bond, such as gray cast iron and ductile iron. Therefore, there is an urgent need to design and develop a cutting tool that combines the characteristics of both high-entropy carbide and high-entropy carbonitride ceramics. Summary of the Invention

[0004] To address the shortcomings and drawbacks of the existing technology, the present invention aims to provide a high-entropy carbide-high-entropy carbonitride ceramic cutting tool. This ceramic cutting tool uses a high-entropy carbide as the cutting tip and a carbonitride ceramic as the flank face. The composition of the high-entropy carbide ceramic is (Ti... 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C is the main component, and high-entropy carbonitride ceramics are based on (Ti) 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 Cx N 1-x Using high-entropy carbonitrides (0.1≤x≤0.9) as the main phase and adding a small amount of metal powder (Co, Ni, Mo) as the reinforcing phase, the cutting tip has higher hardness than high-entropy carbonitrides, while the back face has higher toughness than high-entropy carbides.

[0005] Another object of the present invention is to provide a method for preparing the ceramic cutting tool with the above-mentioned high-entropy carbide tip-high-entropy carbonitride back face structure. This method involves sintering the high-entropy carbide and high-entropy carbonitride in different regions.

[0006] Another object of the present invention is to provide an application of a ceramic cutting tool with a high-entropy carbide tip and a high-entropy carbonitride flank structure. This tool can be used for high-speed cutting of gray cast iron and ductile cast iron.

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

[0008] A ceramic cutting tool with a high-entropy carbide tip-high-entropy carbonitride flank structure includes a high-entropy carbide phase at the tip (Ti). 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C and the high-entropy carbonitride phase on the flank face (Ti) 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C x N 1-x , 0.1≤x≤0.9.

[0009] Preferably, the ceramic cutting tool is prepared by ball milling and mixing TiC, ZrC, NbC, TaC and WC in equimolar ratio to obtain a carbide mixed powder, and by ball milling and mixing TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and Ni powder as a sintering aid to obtain a carbonitride mixed powder; then the carbonitride mixed powder and the carbide mixed powder are placed in a graphite mold one after the other, and held under pressure of 1-3T for 1-3 minutes, and then subjected to spark plasma sintering at 1600-1800℃ under vacuum and pressure of 30-50MPa.

[0010] Preferably, the ceramic cutting tool has a density of 98% or higher, a Vickers hardness of 26–29 GPa for the high-entropy carbide phase, and a fracture toughness of 4–6 MPa·m. 1 / 2 The high-entropy carbonitride phase has a Vickers hardness of 23–25 GPa and a fracture toughness of 7–9 MPa·m. 1 / 2 .

[0011] Preferably, the sintering aid Ni powder is 5-10 vol% of a carbonitride mixed powder.

[0012] The method for preparing the ceramic cutting tool with the high-entropy carbide tip-high-entropy carbonitride flank structure includes the following specific steps:

[0013] S1. Equimolar amounts of TiC, ZrC, NbC, TaC, and WC are mixed, with anhydrous ethanol as the solvent and Si3N4 as the ball milling medium. After ball milling and mixing, the mixture is dried to obtain a carbide mixed powder with the molecular formula (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C;

[0014] S2. TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and Ni powder are mixed, and ball-milled and dried using anhydrous ethanol as solvent and Si3N4 as the ball milling medium to obtain a carbonitride mixed powder with the molecular formula (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C x N 1-x , 0.1≤x≤0.9;

[0015] S3. First, place the carbonitride mixed powder into a graphite mold with a cross-grooved pressure column, and press it with a pressure of 1-3T for 1-3 minutes. Then, replace the cross-grooved pressure column with a round-bottom pressure column and place the carbonitride mixed powder into the graphite mold. Press it with a pressure of 1-3T for 1-3 minutes. Under vacuum, pressurize it with 30-50MPa and sinter it with discharge plasma at 1600-1800℃ to obtain high-entropy carbide-high-entropy carbonitride composite ceramic.

[0016] S4. The high-entropy carbide-high-entropy carbonitride composite ceramic is processed, with the high-entropy carbide as the cutting tip and the high-entropy carbonitride as the back face, to obtain a high-entropy carbide-high-entropy carbonitride ceramic cutting tool.

[0017] Preferably, the heating rate of the discharge plasma sintering in step S3 is 50-150°C / min; and the discharge plasma sintering time is 10-20 min.

[0018] Preferably, the width of the region where the high-entropy carbide tip is located in step S4 is 1.7 to 1.9 cm.

[0019] The application of the ceramic cutting tool with the high-entropy carbide tip-high carbonitride flank structure in high-speed cutting of gray cast iron or ductile iron.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This invention combines high-entropy carbides with high-entropy carbonitride ceramics to prepare ceramic cutting tools with a high-entropy carbide tip-high-entropy carbonitride flank face structure. Using high-entropy carbides as the tip provides higher hardness than high-entropy carbonitride ceramics, while using high-entropy carbonitride as the flank face provides higher fracture toughness than high-entropy carbides, thereby improving the cutting life of the tool.

[0022] 2. The ceramic cutting tool of the present invention has a Vickers hardness of 26-29 GPa and a fracture toughness of 4-6 MPa·m. 1 / 2 The Vickers hardness of the flank face is 23–25 GPa, and the fracture toughness is 7–9 MPa·m. 1 / 2 This ceramic cutting tool can be used for continuous cutting of high-hardness materials such as gray cast iron and ductile iron.

[0023] 3. This invention combines high-entropy carbides with high-entropy carbonitride ceramics. Due to the consistent transition metal composition, the high-entropy carbides and high-entropy carbonitrides diffuse into each other at the bonding surface to form a stable structure, further enhancing the bonding surface strength. The metal added to the high-entropy carbonitrides, upon reaching its melting point and forming a liquid phase, promotes the densification process of the high-entropy carbides, thereby giving the cutting tool stronger cutting performance. Attached Figure Description

[0024] Figure 1 This is a graphite mold designed according to the scheme of the present invention.

[0025] Figure 2 This is a schematic diagram of the high-entropy carbide-high-entropy carbonitride preform of the present invention.

[0026] Figure 3 This is a schematic diagram of a ceramic cutting tool with a high-entropy carbide tip and a high-entropy carbonitride flank face structure according to the present invention. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but these should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0028] Example 1

[0029] 1. Equimolar amounts of TiC (99.9% purity, 1 μm particle size), ZrC (99.9% purity, 1 μm particle size), NbC (99.9% purity, 1 μm particle size), TaC (99.9% purity, 1 μm particle size), and WC (99.9% purity, 1 μm particle size) were ball-milled in anhydrous ethanol as solvent and Si3N4 as the ball milling medium at a speed of 300 r / min for 6 h. The mixture was then dried and sieved to obtain a mixed carbide powder.

[0030] 2. Equimolar ratios of TiC (99.9% purity, 1 μm particle size), ZrC (99.9% purity, 1 μm particle size), NbC (99.9% purity, 1 μm particle size), TaC (99.9% purity, 1 μm particle size), WC (99.9% purity, 1 μm particle size), TiN (99.9% purity, 1 μm particle size), ZrN (99.9% purity, 1 μm particle size), and N... bN (99.9% purity, 1μm particle size), TaN (99.9% purity, 1μm particle size) and WN (99.9% purity, 1μm particle size) were mixed, and then 10 vol% Ni (99.9% purity, 1μm particle size) was added. Using anhydrous ethanol as solvent and Si3N4 as ball milling medium, the mixture was ball-milled at 300 r / min for 6 h. After drying and sieving, a carbonitride mixed powder was obtained.

[0031] 3. Place the carbonitride mixed powder into a graphite mold with a cross-grooved pressing column ( Figure 1 As shown, the pressure is maintained at 1T for 2 minutes. Then, the cross-groove pressure column is replaced with a round-bottom pressure column, and the carbide mixed powder is placed into the graphite mold. The pressure is maintained at 1T for 2 minutes to obtain the green blank. Figure 2 (As shown), the graphite mold is then placed in an SPS sintering furnace. Under vacuum, axial pressure of 30 MPa is applied, and the temperature is increased to 1800 °C at a rate of 100 °C / min and held for 10 min to obtain a high-entropy carbide-high-entropy carbonitride composite ceramic with the molecular formula (Ti). 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C-(Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C 0.75 N 0.25 .

[0032] 4. High-entropy carbide-high-entropy carbonitride composite ceramics are processed, using high-entropy carbide as the cutting tip and high-entropy carbonitride as the flank face, to produce ceramic cutting tools, such as... Figure 3 As shown.

[0033] The ceramic cutting tool with a high-entropy carbide tip-high carbonitride flank structure has a density of 98.8%, a Vickers hardness of 28.2 GPa, and a fracture toughness of 5.2 MPa·m. 1 / 2 The Vickers hardness of the flank face is 24.7 GPa, and the fracture toughness is 8.2 MPa·m. 1 / 2 The cutting life is 2015s.

[0034] Example 2

[0035] The difference from Example 1 is that an axial pressure of 50 MPa is applied in step 3. The ceramic cutting tool of this example has a density of 99.1%, a Vickers hardness of 27.4 GPa at the cutting tip, and a fracture toughness of 4.6 MPa·m. 1 / 2 The Vickers hardness of the flank face is 24.2 GPa, and the fracture toughness is 7.8 MPa·m. 1 / 2 The cutting life is 1910s.

[0036] Example 3

[0037] The difference from Example 1 is that the holding time in step 3 is 15 minutes. The ceramic cutting tool of this example has a density of 98.4%, a Vickers hardness of 26.3 GPa at the tip, and a fracture toughness of 4.5 MPa·m. 1 / 2 The Vickers hardness of the flank face is 23.7 GPa, and the fracture toughness is 7.4 MPa·m. 1 / 2 The cutting life is 1890s.

[0038] Example 4

[0039] The difference from Example 1 is that the sintering temperature in step 3 is 1700℃. The ceramic cutting tool of this example has a density of 98.2%, a Vickers hardness of 26.1 GPa at the tip, and a fracture toughness of 4.1 MPa·m. 1 / 2 The Vickers hardness of the flank face is 23.1 GPa, and the fracture toughness is 7.2 MPa·m. 1 / 2 The cutting life is 1820s.

[0040] The ceramic cutting tool of the present invention has a density of over 98%, wherein the Vickers hardness of the cutting tip is 26-29 GPa, and the fracture toughness is 4-6 MPa·m. 1 / 2 The Vickers hardness of the flank face is 23–25 GPa, and the fracture toughness is 7–9 MPa·m. 1 / 2 The cutting life is 1820s or more, preferably 1820 to 2015s.

[0041] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A ceramic cutting tool made of high-entropy carbide-high-entropy carbonitride, characterized in that, The ceramic cutting tool includes a high-entropy carbide phase (Ti) at the tip. 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C and the high-entropy carbonitride phase on the flank face (Ti) 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C x N 1-x , 0.1≤x≤0.

9.

2. The high-entropy carbide-high-entropy carbonitride ceramic cutting tool according to claim 1, characterized in that, The ceramic cutting tool is prepared by ball milling and mixing TiC, ZrC, NbC, TaC and WC in equimolar ratios to obtain a carbide mixed powder. TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, and WN are then ball milled and mixed with Ni powder as a sintering aid to obtain a carbonitride mixed powder. The carbonitride mixed powder and the carbide mixed powder are then placed sequentially into a graphite mold, held under pressure of 1-3T for 1-3 minutes, and subjected to spark plasma sintering at 1600-1800℃ under vacuum and pressure of 30-50MPa.

3. The high-entropy carbide-high-entropy carbonitride ceramic cutting tool according to claim 1 or 2, characterized in that, The ceramic cutting tool has a density of over 98%, and the high-entropy carbide phase has a Vickers hardness of 26–29 GPa and a fracture toughness of 4–6 MPa·m. 1 / 2 The high-entropy carbonitride phase has a Vickers hardness of 23–25 GPa and a fracture toughness of 7–9 MPa·m. 1 / 2 .

4. The high-entropy carbide-high-entropy carbonitride ceramic cutting tool according to claim 2, characterized in that, The sintering aid Ni powder is 5-10 vol% of a carbonitride mixed powder.

5. The method for preparing a high-entropy carbide-high-entropy carbonitride ceramic cutting tool according to any one of claims 1 to 4, characterized in that, The specific steps include the following: S1. Equimolar amounts of TiC, ZrC, NbC, TaC, and WC are mixed, with anhydrous ethanol as the solvent and Si3N4 as the ball milling medium. After ball milling and mixing, the mixture is dried to obtain a carbide mixed powder with the molecular formula (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C; S2. TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and Ni powder are mixed, and ball-milled and dried using anhydrous ethanol as solvent and Si3N4 as the ball milling medium to obtain a carbonitride mixed powder with the molecular formula (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 C x N 1-x , 0.1≤x≤0.9; S3. First, place the carbonitride mixed powder into a graphite mold with a cross-grooved pressure column, and press it with a pressure of 1-3T for 1-3 minutes. Then, replace the cross-grooved pressure column with a round-bottom pressure column and place the carbonitride mixed powder into the graphite mold. Press it with a pressure of 1-3T for 1-3 minutes. Under vacuum, pressurize it with 30-50MPa and sinter it with discharge plasma at 1600-1800℃ to obtain high-entropy carbide-high-entropy carbonitride composite ceramic. S4. The high-entropy carbide-high-entropy carbonitride composite ceramic is processed, with the high-entropy carbide as the cutting tip and the high-entropy carbonitride as the back face, to obtain a high-entropy carbide-high-entropy carbonitride ceramic cutting tool.

6. The method for preparing the high-entropy carbide-high-entropy carbonitride ceramic cutting tool according to claim 5, characterized in that, The heating rate of the discharge plasma sintering in step S3 is 50-150℃ / min; the discharge plasma sintering time is 10-20min.

7. The application of the high-entropy carbide-high-entropy carbonitride ceramic cutting tool according to any one of claims 1 to 4 in high-speed cutting of gray cast iron or ductile cast iron.

Images