Polycrystalline diamond compact, preparation method thereof and cutting tool

Abstract

The embodiment of the invention provides a polycrystalline diamond compact and a preparation method thereof and a cutting tool, the polycrystalline diamond compact comprises a three-dimensional skeleton and polycrystalline diamond filled in the three-dimensional skeleton, the three-dimensional skeleton comprises two-dimensional network layers arranged at intervals and first metal wires supporting the two-dimensional network layers, and the two-dimensional network layer comprises metal wires with a grid structure and carbon fibers woven on the metal wires. A tough three-dimensional network composed of metal wires and carbon fibers is arranged in polycrystalline diamond, the polycrystalline diamond is divided into a plurality of small units, when one small unit is cracked, the tough network stretches across cracks, rapid expansion of the cracks is prevented through tension transmission, yield of the tough network needs to consume a large amount of energy, damage to the whole structure is delayed, and the service life of the polycrystalline diamond is prolonged. The compressive strength and ductility of the polycrystalline diamond compact can be improved by the circumferential constraint of the toughness network on the surrounding polycrystalline diamond, the shear failure is inhibited, and the fracture toughness of the polycrystalline diamond compact is improved.

Description

Technical Field

[0001] This application relates to the field of polycrystalline diamond composite sheets, and more particularly to a polycrystalline diamond composite sheet, its preparation method, and a cutting tool thereof. Background Technology

[0002] Existing polycrystalline diamond composite sheets use diamond particles as a framework and metal as a binder to form polycrystalline diamond aggregates. However, their fracture toughness is poor, much lower than that of cemented carbide matrices, and crack propagation paths are unimpeded.

[0003] Currently, most methods involve surface coating with hard coatings such as TiC / TiN or adding short fibers (e.g., carbon fibers with a length of <1mm), but these methods cannot form cross-size stress transfer paths and cannot effectively solve the problem of poor fracture toughness. Summary of the Invention

[0004] This application provides polycrystalline diamond composite sheets, their preparation methods, and cutting tools to improve the fracture toughness of polycrystalline diamond composite sheets.

[0005] In a first aspect, embodiments of this application provide a polycrystalline diamond composite sheet, comprising: a three-dimensional framework, and polycrystalline diamond filling the three-dimensional framework;

[0006] The three-dimensional skeleton includes two-dimensional network layers arranged at intervals, and a first metal wire supporting the two-dimensional network layers;

[0007] The two-dimensional network layer includes a second metal wire with a mesh structure and carbon fibers woven on the second metal wire.

[0008] In one possible implementation, the plurality of said two-dimensional network layers are arranged at equal intervals;

[0009] In the vertical direction of the three-dimensional skeleton, the pores in the multiple two-dimensional network layers decrease sequentially.

[0010] In one possible implementation, the carbon fibers are woven between a pair of opposite corners of the mesh structure.

[0011] In one possible implementation, the metal corresponding to the first metal wire includes at least one of Co, Cr, Fe, Ni, and eutectic high-entropy alloy;

[0012] And / or, the metal corresponding to the second metal wire includes at least one of Co, Cr, Fe, Ni, and eutectic high-entropy alloy;

[0013] And / or, the carbon fibers include polyacrylonitrile-based carbon fibers.

[0014] In one possible implementation, the diameter of the first metal wire is 0.1mm-0.5mm;

[0015] And / or, the length of the first metal wire is 3cm-80cm;

[0016] And / or, the diameter of the second metal wire is 0.1mm-0.5mm;

[0017] And / or, the length of the second metal wire is 3cm-7cm;

[0018] And / or, the diameter of the carbon fiber is 5μm-10μm;

[0019] And / or, the length of the carbon fiber is 3mm-5mm.

[0020] In a second aspect, a method for preparing a polycrystalline diamond composite sheet as described in the first aspect, the method comprising:

[0021] The first metal wire is welded to a two-dimensional network layer arranged at intervals to obtain a three-dimensional skeleton;

[0022] Diamond micro powder is filled into the three-dimensional framework to obtain a three-dimensional composite.

[0023] The three-dimensional composite is subjected to high temperature and high pressure treatment to obtain the polycrystalline diamond composite sheet.

[0024] In one possible implementation, filling the three-dimensional framework with diamond micropowder to obtain a three-dimensional composite includes:

[0025] Under filtration and drying conditions, diamond micro powder is filled into the three-dimensional framework to obtain a three-dimensional composite.

[0026] And / or, subjecting the three-dimensional composite to high-temperature and high-pressure treatment to obtain the polycrystalline diamond composite sheet, comprising:

[0027] The polycrystalline diamond composite sheet is obtained by applying a pressure of 6 GPa to 9 GPa to the three-dimensional composite material at a temperature of 1400℃-1800℃.

[0028] In one possible implementation, the method further includes:

[0029] Arrange the second metal wires into a mesh structure;

[0030] After weaving carbon fibers onto the second metal wire, a cold pressing process is performed to obtain the two-dimensional network layer.

[0031] In one possible implementation, the method further includes:

[0032] After ultrasonic cleaning by immersing the carbon fiber in acetone, it is subjected to vacuum heat treatment at 400℃-500℃ for 1-2 hours.

[0033] Thirdly, this application provides a cutting tool, including the polycrystalline diamond composite sheet described in the first aspect, or the polycrystalline diamond composite sheet prepared by the preparation method described in the second aspect.

[0034] The polycrystalline diamond composite sheet, its preparation method, and cutting tool provided in this application include a three-dimensional skeleton and polycrystalline diamond filled within the three-dimensional skeleton. The three-dimensional skeleton includes spaced-apart two-dimensional network layers and a first metal wire supporting the two-dimensional network layers. The two-dimensional network layers include metal wires with a mesh structure and carbon fibers woven onto the metal wires. By setting a tough three-dimensional network composed of metal wires and carbon fibers in the polycrystalline diamond, the polycrystalline diamond is divided into multiple small units. When a small unit cracks, the tough network spans the crack, preventing rapid crack propagation through tensile force transmission. Furthermore, the yielding of the tough network requires a large amount of energy, delaying the overall structural failure. The circumferential constraint of the tough network on the surrounding polycrystalline diamond can improve the compressive strength and ductility of the polycrystalline diamond composite sheet and suppress shear failure. In addition, the carbon fibers and metal wires consume energy when pulled out or broken in the crack, delaying further crack propagation and improving the fracture toughness of the polycrystalline diamond composite sheet. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] Figure 1 This is a schematic diagram of the structure of the polycrystalline diamond composite sheet provided in this application;

[0037] Figure 2 A schematic diagram of the structure of the two-dimensional network layer provided in this application;

[0038] Figure 3 A schematic diagram of the three-dimensional skeleton provided in this application.

[0039] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0040] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0041] First, let me explain the terms used in this application:

[0042] Polycrystalline diamond compact (PDC): also known as PDC tooth, is made by sintering a top layer of synthetic diamond micropowder and a bottom layer of cemented carbide matrix at high temperature. The polycrystalline diamond (PCD) layer acts as the cutting edge, directly undertaking the cutting action in the rock-breaking process, while the cemented carbide matrix provides support, buffering and heat conduction for the polycrystalline diamond layer. The synergistic effect of the polycrystalline diamond layer and the cemented carbide matrix enables the polycrystalline diamond compact to maintain high rock-breaking ability under complex geological conditions.

[0043] Polyacrylonitrile (PAN)-based carbon fiber: This is a high-performance fiber material made from polyacrylonitrile fibers through pre-oxidation, carbonization, graphitization, and other steps, with a carbon content exceeding 95%. PAN-based carbon fiber possesses high strength and chemical stability, with a strength of 3-7 GPa and a modulus of approximately 200-700 GPa, superior to most metallic materials. It maintains structural stability above 2000℃ and is resistant to acid and alkali corrosion.

[0044] Existing polycrystalline diamond composite sheets use diamond particles as a framework and metal as a binder to form polycrystalline diamond aggregates. However, their fracture toughness is poor, much lower than that of cemented carbide matrices, and crack propagation paths are unimpeded.

[0045] Currently, most methods involve surface coating with hard coatings such as TiC / TiN or adding short fibers (e.g., carbon fibers with a length of <1mm), but these methods cannot form cross-size stress transfer paths and cannot effectively solve the problem of poor fracture toughness.

[0046] Furthermore, existing polycrystalline diamond composite sheets are prone to shear failure under impact loads (such as when a drill bit encounters a hard interlayer). The matrix has relatively low plastic deformation capacity, resulting in low energy absorption efficiency. Consequently, the impact energy cannot be dissipated through plastic deformation and is directly converted into crack propagation kinetic energy, making polycrystalline diamond composite sheets more prone to chipping or overall fracture in hard rock interlayers.

[0047] To address this, this application proposes a polycrystalline diamond composite sheet, comprising a three-dimensional skeleton and polycrystalline diamonds filling the three-dimensional skeleton. The three-dimensional skeleton includes spaced-apart two-dimensional network layers, and the two-dimensional network layers include metal wires with a mesh structure and carbon fibers woven onto the metal wires. By setting a tough three-dimensional network composed of metal wires and carbon fibers within the polycrystalline diamond, the polycrystalline diamond is divided into multiple small units. When a small unit cracks, the tough network spans the crack, preventing rapid crack propagation through tensile force transmission. Furthermore, the yielding of the tough network requires a large amount of energy, delaying the overall structural failure. The circumferential constraint of the tough network on the surrounding polycrystalline diamond can improve the compressive strength and ductility of the polycrystalline diamond composite sheet and suppress shear failure. In addition, the carbon fibers and metal wires consume energy when pulled out or broken in the crack, delaying further crack propagation. Therefore, by adding tough fibers to polycrystalline diamond and creating a regular structural design, the crack resistance, ductility, and energy dissipation capacity of the polycrystalline diamond composite sheet can be improved, achieving high toughness and extending its service life.

[0048] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0049] Figure 1 This is a schematic diagram of the structure of the polycrystalline diamond composite sheet of this application, as shown below. Figure 1 As shown, the polycrystalline diamond composite sheet provided in this application embodiment includes:

[0050] A three-dimensional framework, and polycrystalline diamond filling the three-dimensional framework;

[0051] The three-dimensional skeleton includes two-dimensional network layers arranged at intervals, and a first metal wire supporting the two-dimensional network layers;

[0052] The two-dimensional network layer includes a second metal wire with a grid structure and carbon fibers woven on the second metal wire.

[0053] In this embodiment, the polycrystalline diamond composite sheet includes a three-dimensional skeleton, similar to a steel frame in construction, which provides shock absorption, impact resistance, and energy absorption. The polycrystalline diamond composite sheet formed by filling the three-dimensional skeleton with polycrystalline diamond resembles a reinforced concrete structure. The three-dimensional skeleton includes multiple spaced two-dimensional network layers, each comprising a second metal wire with a mesh structure and carbon fibers woven onto the second metal wire. The metal wire possesses good toughness, while the carbon fibers prevent crack formation and propagation. The three-dimensional toughness network composed of the metal wire and carbon fibers can traverse crack propagation paths, and the pull-out energy dissipation mechanism of the carbon fibers and metal wires requires crack propagation to overcome multiple energy barriers, thus increasing the fracture toughness of the polycrystalline diamond composite sheet by 40%-60%. Furthermore, the three-dimensional network can divide the polycrystalline diamond into multiple independent units, inhibiting cross-regional crack propagation, thereby significantly improving the impact toughness of the polycrystalline diamond composite sheet.

[0054] The three-dimensional network can also guide uniform stress distribution and reduce peak contact stress. Under dynamic loads, the metal wires yield and dissipate energy, achieving adaptive adjustment of impact resistance. The metal skeleton can also form a three-dimensional heat conduction network, improving thermal conductivity. Combined with a diamond phase change buffer layer, it enhances thermal stability and is suitable for drilling in high-temperature formations above 200℃.

[0055] For example, during the process of filling polycrystalline diamond into a three-dimensional skeleton, the metal wire skeleton melts and infiltrates into the polycrystalline diamond in the skeleton pores. The liquid metal dissolves the graphite on the surface of the diamond particles and catalyzes its formation into diamond, causing the diamond particles to grow and overlap, forming a dense sintered body with diamond-diamond bonds, that is, forming a polycrystalline diamond composite sheet.

[0056] For example, the metal corresponding to the wire can be a transition metal, which has good ductility and toughness and can form a strong bonding interface between the diamond particles and the matrix material, thereby improving the strength and toughness of the polycrystalline diamond composite sheet.

[0057] In this embodiment, the two-dimensional network layer includes a second metal wire with a mesh structure and carbon fibers woven on the second metal wire. The metal wire has good toughness, and the carbon fibers can prevent the formation and propagation of cracks. The three-dimensional skeleton includes two-dimensional network layers arranged at intervals and a first metal wire supporting the two-dimensional network layers. The three-dimensional skeleton includes multiple interconnected pores, and polycrystalline diamond is filled in the pores to form a polycrystalline diamond composite sheet.

[0058] In one possible implementation, such as Figure 2As shown, the two-dimensional network layer comprises a mesh constructed from second metal wires and carbon fibers wound around the mesh. The carbon fibers are woven between a pair of opposite corners of the mesh structure, which helps to evenly distribute the stress applied to the structure and reduce the risk of fracture.

[0059] In one possible implementation, multiple two-dimensional network layers are arranged at equal intervals, and the porosity of the multiple two-dimensional network layers decreases sequentially in the vertical direction of the three-dimensional skeleton. This results in a continuous decrease in the particle size of the polycrystalline diamond layers between the two-dimensional network layers, forming a gradient interface structure, which is conducive to the formation of a multi-level crack bridging mechanism. The multi-level crack bridging mechanism refers to the ability of certain structures or phases (such as fibers, particles, etc.) within the material to cross the crack surface and form a bridging effect when a crack propagates in the material. Through multi-level bridging, the crack propagation rate can be slowed down, thereby improving the fracture toughness of the polycrystalline diamond composite sheet.

[0060] For example, the first metal wire and the second metal wire can be the same metal or different metals.

[0061] In one possible implementation, the metal corresponding to the first metal wire includes at least one of Co, Cr, Fe, Ni, and a eutectic high-entropy alloy. Cobalt (Co) is used as a binder, effectively binding diamond particles and improving the overall strength and toughness of the material. Co also possesses good wear resistance, which can improve the service life of the polycrystalline diamond composite sheet in high-wear environments. Chromium (Cr) has excellent corrosion resistance, improving the durability of the polycrystalline diamond composite sheet in corrosive environments and increasing the material's hardness, thus enhancing its wear resistance. Iron (Fe) can form alloys with other metals, improving the material's mechanical properties. Nickel (Ni) has good toughness and ductility, improving the impact resistance of the polycrystalline diamond composite sheet. The eutectic high-entropy alloy, composed of multiple metals, possesses excellent comprehensive properties, such as high strength, high hardness, and good thermal stability. Furthermore, the complex phase structure of the eutectic high-entropy alloy can improve the material's thermal stability and fatigue resistance.

[0062] In one possible implementation, the metal corresponding to the second metal wire may also include at least one of Co, Cr, Fe, Ni, and eutectic high-entropy alloys.

[0063] In one possible implementation, the carbon fiber includes polyacrylonitrile-based carbon fiber, which has high toughness, high tensile strength and high thermal stability. Weaving polyacrylonitrile-based carbon fiber around a metal wire skeleton helps to improve the strength and stability of the polycrystalline diamond composite sheet.

[0064] For example, metal wires can be classified according to their thickness into coarse wires, fine wires, micro wires, and fibers. Generally speaking, metal wires have a diameter between 0.1mm and 3.2mm, while metal wires with a diameter less than 100μm are called metal fibers. The manufacturing process and equipment differ depending on the thickness of the metal wire. Coarse wires are generally drawn using a continuous tank drawing machine, medium and fine wires are generally drawn using a water tank drawing machine, and micro wires are suitable for CNC micro-drawing machines. Metal fibers are resistant to high temperatures and corrosion, have high thermal and electrical conductivity, and also possess high elasticity, strength, and wear resistance. Furthermore, they exhibit excellent properties such as sinterability and spinnability.

[0065] In one possible implementation, the diameter of the first metal wire is 0.1mm-0.5mm. The first metal wire being within this range helps to form a mesh structure by bending, and also helps to improve the overall mechanical strength and stability.

[0066] For example, the diameter of the first metal wire may include a range of 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, or any combination thereof.

[0067] In one possible implementation, the diameter of the second metal wire is 0.1 mm to 0.5 mm. The second metal wire being within this range helps to support each two-dimensional network layer.

[0068] For example, the diameter of the second metal wire may include a range of 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, or any combination thereof.

[0069] In one possible implementation, the length of the first metal wire is 3cm-80cm. The length of the first metal wire within this range helps to form a porous mesh structure, which facilitates the filling of polycrystalline diamond into the three-dimensional skeleton.

[0070] For example, the length of the first metal wire may include a range of 3cm, 5cm, 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm, 80cm, or any two of these.

[0071] In one possible implementation, the length of the second metal wire is 3cm-7cm. The length of the second metal wire is within this range and adjusted according to the thickness of the diamond layer, which helps to ensure that the height of the polycrystalline diamond composite sheet is within a suitable range.

[0072] For example, the length of the second metal wire may include a range of 3cm, 3.5cm, 4cm, 4.5cm, 5cm, 5.5cm, 6cm, 6.5cm, 7cm, or any two of these.

[0073] In one possible implementation, the carbon fiber has a diameter of 5μm-10μm. This diameter range helps to form an effective load transfer network, uniformly distribute stress, and improve the toughness of the material.

[0074] For example, the diameter of the carbon fiber is in the range of 5μm, 6μm, 7μm, 8μm, 9μm, 10μm or any combination thereof.

[0075] In one possible implementation, the carbon fiber is 3mm-5mm long, for example, the carbon fiber between a pair of diagonals in the mesh structure is 3mm-5mm long, which helps to weave the carbon fiber between the mesh structures.

[0076] For example, the length of the carbon fiber is a range of 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or any two of these.

[0077] This application also provides a method for preparing polycrystalline diamond composite sheets, comprising the following steps:

[0078] S101. Weld the first metal wire to the spaced two-dimensional network layer to obtain a three-dimensional skeleton.

[0079] For example, multiple first metal wires are welded and fixed to the nodes of each two-dimensional network layer to obtain a three-dimensional skeleton. For instance, the first metal wires are welded to the nodes of the two-dimensional network layers, and multiple two-dimensional network layers are arranged at equal intervals to form a regular three-dimensional spatially connected porous complex, such as... Figure 3 As shown, this helps to prevent carbon fiber agglomeration and enhances the regularity of the tough network spatial structure.

[0080] In one possible implementation, the second metal wires are arranged into a network structure, and carbon fibers are woven onto the second metal wires, followed by cold pressing to obtain a two-dimensional network layer. Cold pressing forms a two-dimensional network layer of a specific shape and size, and can increase the density of the two-dimensional network layer, thereby improving its mechanical properties and stability.

[0081] For example, metal wires are arranged in a certain pattern to form a blank, which is then placed in a circular mold and cold-pressed to form a two-dimensional network layer.

[0082] For example, metal wires with a diameter of 0.1 mm to 0.5 mm and a length of 3 cm to 80 cm can be prepared using the melt-drawing method.

[0083] In one possible implementation, the carbon fiber can be immersed in acetone and ultrasonically cleaned at room temperature for 20-30 minutes, followed by vacuum heat treatment at 400℃-500℃ for 1-2 hours. Ultrasonic cleaning removes the surface organic coating and impurities, while heat treatment removes surface impurities.

[0084] S102. Fill the three-dimensional framework with diamond micro powder to obtain a three-dimensional composite.

[0085] In one possible implementation, diamond micropowder is filled into a three-dimensional framework under conditions of filtration and drying to obtain a three-dimensional composite.

[0086] For example, using an oil-free diaphragm small vacuum pump at a pumping rate of 10 L / min, diamond slurry with anhydrous ethanol as solvent is filtered and filled using a sand core filter device and a 0.45 μm microporous filter membrane. The filtered composite is then placed on a heating table and dried at 90 °C for 30 min. High-quality synthetic diamond micropowder is filled into the pores of the three-dimensional framework using the above method to obtain a three-dimensional composite.

[0087] For example, the particle size of diamond micron powder can be 5μm-25μm. When the particle size of diamond micron powder is within this range, it helps to improve the cutting efficiency and wear resistance of polycrystalline diamond composite sheets.

[0088] For example, the particle size of diamond micron powder is a range of 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, or any combination thereof.

[0089] S103. The three-dimensional composite is subjected to high temperature and high pressure treatment to obtain polycrystalline diamond composite sheet.

[0090] In one possible implementation, a polycrystalline diamond composite sheet is obtained by applying a pressure of 6 GPa to 9 GPa to the three-dimensional composite at a temperature of 1400℃ to 1800℃. Under high temperature and high pressure conditions, the metal wire skeleton melts and infiltrates into the polycrystalline diamond in the skeleton pores. The liquid metal dissolves the graphite on the surface of the diamond particles and catalyzes its formation into diamond, causing the diamond particles to grow and overlap, forming a dense sintered body with diamond-diamond bonds, i.e., forming a polycrystalline diamond composite sheet.

[0091] For example, a three-dimensional composite is processed under the high temperature and high pressure conditions of a six-sided top large cavity press.

[0092] For example, the high temperature can be a range of 1400°C, 1450°C, 1500°C, 1550°C, 1600°C, 1650°C, 1700°C, 1750°C, 1800°C, or any combination thereof.

[0093] For example, the high pressure can be a range of 6 GPa, 6.5 GPa, 7 GPa, 7.5 GPa, 8 GPa, 8.5 GPa, 9 GPa, or any combination thereof.

[0094] This application also provides a cutting tool, including the polycrystalline diamond composite sheet described above, or the polycrystalline diamond composite sheet prepared by the above preparation method.

[0095] For example, cutting tools may include drill teeth, cutting tools, etc.

[0096] The present invention will be further described below through specific embodiments.

[0097] Example 1

[0098] (1) Immerse carbon fibers with a length of 5 mm and a diameter of 6 μm in acetone, ultrasonically clean them for 20 min, and then vacuum heat treat them at 400 °C for 1 h.

[0099] (2) Bend a metal wire with a length of 80cm and a diameter of 0.1mm into a mesh structure, and weave the carbon fiber obtained in step (1) onto the mesh structure;

[0100] (3) Place the woven carbon fiber mesh structure obtained in step (2) into a circular hard alloy mold, and perform cold pressing treatment by repeating the process more than twice with a single-column hydraulic press with a force of 50kN to obtain a two-dimensional network layer.

[0101] (4) Weld a metal wire with a length of 3cm and a diameter of 0.5mm to three two-dimensional network layers at equal intervals to obtain a three-dimensional skeleton;

[0102] (5) Using an oil-free diaphragm small vacuum pump, at a pumping rate of 10L / min, diamond slurry with anhydrous ethanol as solvent is filtered and filled using a sand core filter device and a 0.45μm microporous filter membrane.

[0103] (6) Place the composite material after filtration in step (5) on a heating table and dry it at 90°C for 30 min to obtain a three-dimensional composite material;

[0104] (7) The three-dimensional composite in step (6) is subjected to high temperature and high pressure treatment at 7 GPa and 1650℃ using a six-sided top large cavity press to obtain polycrystalline diamond composite sheet (PDC cutting teeth).

[0105] Comparative Example 1

[0106] Diamond micropowder with a particle size of 15 μm was sintered under sintering conditions of 7 GPa and 1500 °C to obtain ordinary commercial PDC cutting teeth.

[0107] The impact resistance of the PDC cutting teeth was evaluated using a drop hammer impact testing machine in both Example 1 and Comparative Example 1. The PDC cutting teeth were brazed to a base at a 15° angle. A cylindrical WC-16Co cemented carbide target was used, and the composite blade edge was impacted with an initial energy of 2 J. With each impact, the energy was increased by 2 J, and the target was rotated to move the unimpacted area of ​​the target above the PDC cutting tooth edge. This operation was repeated until the PDC cutting teeth failed. The energy at the initial crack formation and final failure of the PDC cutting teeth was recorded during the impact process.

[0108] Experiments showed that the final fracture energy of a typical commercial PDC cutting tooth is 328 J, while the final fracture energy of the polycrystalline diamond composite sheet in this embodiment is 508 J, representing an improvement in fracture toughness of approximately 55%. Through gradient optimization of diamond particle size, the final fracture energy of the polycrystalline diamond composite sheet reached 590 J, with an improvement in fracture toughness of approximately 79%. Simultaneously, microcrack observation of the fracture surface revealed that when the microcrack approaches the metal skeleton region, it bifurcates, and secondary cracks enter adjacent polycrystalline diamond segmented unit regions. The main crack deflects and continues to propagate in a near-horizontal direction within the unit region. Subsequently, during propagation, it encounters carbon fibers within the unit region. The bridging effect of the fibers significantly inhibits crack propagation, and the microcrack stops further propagation after entering this region. Therefore, the three-dimensional metal-carbon fiber network of this embodiment effectively suppresses cross-regional crack propagation.

[0109] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A polycrystalline diamond composite sheet, characterized in that, include: A three-dimensional framework, and polycrystalline diamond filling the three-dimensional framework; The three-dimensional skeleton includes two-dimensional network layers arranged at intervals, and a first metal wire supporting the two-dimensional network layers; The two-dimensional network layer includes a second metal wire with a mesh structure and carbon fibers woven on the second metal wire.

2. The polycrystalline diamond composite sheet according to claim 1, characterized in that, Multiple two-dimensional network layers are arranged at equal intervals; In the vertical direction of the three-dimensional skeleton, the pores in the multiple two-dimensional network layers decrease sequentially.

3. The polycrystalline diamond composite sheet according to claim 1, characterized in that, The carbon fibers are woven between a pair of opposite corners of the mesh structure.

4. The polycrystalline diamond composite sheet according to any one of claims 1-3, characterized in that, The metal corresponding to the first metal wire includes at least one of Co, Cr, Fe, Ni, and eutectic high entropy alloy; And / or, the metal corresponding to the second metal wire includes at least one of Co, Cr, Fe, Ni, and eutectic high-entropy alloy; And / or, the carbon fibers include polyacrylonitrile-based carbon fibers.

5. The polycrystalline diamond composite sheet according to any one of claims 1-3, characterized in that, The diameter of the first metal wire is 0.1mm-0.5mm; And / or, the length of the first metal wire is 3cm-80cm; And / or, the diameter of the second metal wire is 0.1mm-0.5mm; And / or, the length of the second metal wire is 3cm-7cm; And / or, the diameter of the carbon fiber is 5μm-10μm; And / or, the length of the carbon fiber is 3mm-5mm.

6. A method for preparing a polycrystalline diamond composite sheet as described in any one of claims 1-5, characterized in that, The method includes: The first metal wire is welded to a two-dimensional network layer arranged at intervals to obtain a three-dimensional skeleton; Diamond micro powder is filled into the three-dimensional framework to obtain a three-dimensional composite. The three-dimensional composite is subjected to high temperature and high pressure treatment to obtain the polycrystalline diamond composite sheet.

7. The preparation method according to claim 6, characterized in that, The process of filling the three-dimensional framework with diamond micropowder to obtain a three-dimensional composite includes: Under filtration and drying conditions, diamond micro powder is filled into the three-dimensional framework to obtain a three-dimensional composite. And / or, subjecting the three-dimensional composite to high-temperature and high-pressure treatment to obtain the polycrystalline diamond composite sheet, comprising: The polycrystalline diamond composite sheet is obtained by applying a pressure of 6 GPa to 9 GPa to the three-dimensional composite material at a temperature of 1400℃-1800℃.

8. The preparation method according to claim 6 or 7, characterized in that, The method further includes: Arrange the second metal wires into a mesh structure; After weaving carbon fibers onto the second metal wire, a cold pressing process is performed to obtain the two-dimensional network layer.

9. The preparation method according to claim 8, characterized in that, The method further includes: After immersing the carbon fiber in acetone and ultrasonically cleaning for 20-30 minutes, it is subjected to vacuum heat treatment at 400℃-500℃ for 1-2 hours.

10. A cutting tool, characterized in that, This includes the polycrystalline diamond composite sheet according to any one of claims 1-5, or the polycrystalline diamond composite sheet prepared by the preparation method according to any one of claims 6-9.

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