High-strength wear-resistant cutting tool and preparation method thereof

Abstract

The invention relates to the technical field of cutting tools, and discloses a high-strength wear-resistant cutting tool and a preparation method thereof.The high-strength wear-resistant cutting tool is prepared from, by weight, 85-89.5 parts of tungsten carbide nanometer powder, 9-12 parts of cobalt powder, 0.5-1 part of chromium carbide, 1-2 parts of tantalum powder and 0-0.5 part of molybdenum powder, and the particle size range of the tungsten carbide nanometer powder is 50-100 nm. The synergistic effect of the tungsten carbide nano powder and the gradient cobalt content is accurately controlled, breakthrough improvement of the performance of a base material is achieved, the gradient structure design enables the surface layer of the material to obtain high hardness, meanwhile, the core part keeps fracture toughness, and the technical problem that a traditional homogeneous material cannot give consideration to high hardness and high toughness is solved. And the cutting tool can adapt to wider machining working conditions and material types.

Description

Technical Field

[0001] The present invention relates to the technical field of cutting tools, and particularly to a high-strength wear-resistant cutting tool and a preparation method thereof. Background Art

[0002] Traditional tools are prone to problems such as wear and chipping when machining high-hardness or high-toughness materials, which affect machining accuracy and efficiency. To this end, modern technologies improve hardness and thermal stability by using matrix materials such as ultrafine-grained cemented carbide, ceramics (such as Al2O3 / TiC), or cubic boron nitride (CBN); combine physical vapor deposition (PVD) or chemical vapor deposition (CVD) processes to apply wear-resistant coatings such as TiAlN and AlCrN to reduce the friction coefficient and enhance the high-temperature oxidation resistance. In addition, by optimizing the tool geometric angles (such as rake angle and edge inclination angle) and edge strengthening treatment (such as passivation and chamfering), the cutting force distribution and heat dissipation capacity are further improved, so as to achieve a longer tool life and stable machining quality under high-speed and heavy-load working conditions.

[0003] In the manufacturing of traditional cutting tools, cemented carbide usually adopts a mixed structure of homogeneous tungsten carbide (WC) and cobalt (Co), and the cobalt content is adjusted to balance the hardness and toughness of the material. However, a high cobalt content can improve fracture toughness but will reduce hardness and wear resistance; while a low cobalt content can enhance hardness but will increase the brittleness of the material, making it prone to chipping or fracture during cutting. This makes it difficult for traditional homogeneous cemented carbide tools to simultaneously meet the requirements of high hardness and high toughness, restricting the application range of the tools under complex working conditions. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a high-strength wear-resistant cutting tool and a preparation method thereof, which solve the problem that it is difficult to simultaneously meet the requirements of high hardness and high toughness, restricting the application range of the tool under complex working conditions.

[0005] To achieve the above object, the present invention is realized through the following technical solutions: A high-strength wear-resistant cutting tool, including the following parts by weight: tungsten carbide nanopowder: 85 - 89.5 parts, cobalt powder: 9 - 12 parts, chromium carbide: 0.5 - 1 part, tantalum powder: 1 - 2 parts, molybdenum powder: 0 - 0.5 part, and the particle size range of the tungsten carbide nanopowder is 50 - 100 nm.

[0006] Preferably, a preparation method of a high-strength wear-resistant cutting tool, the method includes the following steps:

[0007] S1. Weigh tungsten carbide nanopowder, cobalt powder, chromium carbide, tantalum powder, and molybdenum powder, mix them, then perform ball milling treatment, and then load them into a graphite mold and place them in a hot pressing sintering furnace to obtain a gradient matrix;

[0008] S2. Load the gradient substrate into a pulsed magnetron sputtering equipment, use a TiSi target, and perform bottom layer deposition;

[0009] S3. Then alternately use an AlCr target and an AlCrO target to deposit and form an AlCrON intermediate layer;

[0010] S4. Finally, transfer it to a laser-assisted chemical vapor deposition equipment, use Al(CH3)3 + H2O as a precursor to deposit an α-Al2O3 coating, and finally form a preliminary cutting tool;

[0011] S5. Then use a femtosecond laser processing system to machine the rake face of the cutting tool to form a micro-pit array;

[0012] S6. Finally, place the cutting tool in a vacuum impregnation equipment for impregnation and dry it using a drying oven.

[0013] Preferably, in S1, a three-dimensional mixer is used for mixing for 30 - 60 minutes, a planetary ball mill is used for ball milling, ball milling is carried out for 4 - 6 hours under argon protection at a rotation speed of 200 - 300 r / min. After being placed in a hot press sintering furnace, it is heated to 1180 - 1220 °C at a rate of 8 - 12 °C / min under argon protection, an axial pressure of 45 - 55 MPa is applied and maintained for 4 - 6 minutes, and at the same time, an 8 - 12 kHz pulsed electromagnetic field is applied using an electromagnetic generating device to obtain a gradient substrate with a surface cobalt content of 5.5 - 6.5% and a core cobalt content of 11.5 - 12.5%.

[0014] Preferably, in S2, the silicon content of the TiSi target is 7 - 9 at%, in an Ar / N2 mixed atmosphere with an N2 partial pressure of 0.3 - 0.5 Pa, the substrate temperature is controlled at 380 - 420 °C, the bias voltage is -90 - -110 V, and the deposition rate is 0.25 - 0.35 μm / h to form a TiSiN bottom layer with a thickness of 0.8 - 1.2 μm.

[0015] Preferably, in S3, during deposition, the O2 partial pressure is controlled by a mass flowmeter to gradually increase from an initial 0.08 - 0.12 Pa to 0.28 - 0.32 Pa, deposit [AlCrN(8 - 12 nm) / AlCrO(4 - 6 nm)] × 18 - 22 cycles, and the total thickness of the finally formed intermediate layer is 2.8 - 3.2 μm.

[0016] Preferably, in S4, when forming the α-Al2O3 surface layer, the laser power is controlled at 480 - 520 W, the substrate temperature is 580 - 620 °C, the deposition rate is 1.1 - 1.3 μm / h, and the finally formed thickness is 4.8 - 5.2 μm.

[0017] Preferably, in the step S5, the femtosecond laser processing system has a wavelength of 1060 - 1080 nm, a pulse width of 100 - 150 fs, and a scanning speed of 190 - 210 mm / s. Micro-pit arrays with a diameter of 48 - 52 μm, a depth of 14 - 16 μm, and a pitch of 98 - 102 μm are processed on the rake face of the tool.

[0018] Preferably, in the step S6, molybdenum disulfide powder with a particle size of 0.8 - 1.2 μm is used for impregnation. The impregnation is carried out for 28 - 32 minutes under a vacuum degree of 1×10-3 - 5×10-3 Pa. After being transferred to the drying oven, it is cured at 80 - 100 °C for 1 - 2 hours to finally obtain the finished tool.

[0019] Preferably, before the step S2, the surface of the substrate is treated by Ar ion bombardment with an energy of 50 - 80 eV and an incident angle of 45 - 60°, forming an activation layer with a surface roughness Ra of 0.2 - 0.3 μm.

[0020] Preferably, in the step S5, dual-beam femtosecond laser processing is adopted. The energy density of the main beam is 2 - 3 J / cm 2 , and the energy density of the auxiliary beam is 0.5 - 1.0 J / cm 2 . The included angle between the two beams is 20 - 30°, forming hemispherical pits with a bottom curvature radius of 20 - 25 μm.

[0021] The present invention provides a high-strength wear-resistant cutting tool and its preparation method, which has the following beneficial effects:

[0022] 1. By precisely controlling the synergistic effect of tungsten carbide nano-powders and the gradient cobalt content, the present invention achieves a breakthrough improvement in the performance of the substrate material. The gradient structure design enables the surface layer of the material to obtain high hardness while the core maintains fracture toughness, solving the technical problem that traditional homogeneous materials cannot balance high hardness and high toughness, and enabling the cutting tool to adapt to a wider range of machining conditions and material types.

[0023] 2. By combining the nano-columnar crystal structure of the TiSiN bottom layer with the oxygen gradient design of the AlCrON intermediate layer, the present invention constructs a multi-layer coating system with stress gradient release characteristics, improving the coating interface bonding strength and the number of thermal shock cycles, and enhancing the service stability and service life of the coating under extreme working conditions.

[0024] 3. By depositing the α-Al2O3 surface layer through laser-assisted CVD technology, the present invention realizes the preferential orientation growth of the (012) crystal plane, not only obtaining a high-hardness alumina coating of good quality but also avoiding the damage to the performance of the substrate material caused by the traditional high-temperature CVD process. While improving the wear resistance of the coating, the excellent mechanical properties of the substrate are maintained.

[0025] 4. The present invention utilizes the dual-beam femtosecond laser processing technology to prepare a regular micro-pit array on the rake face of the cutting tool, realizing the precise control of the surface texture. This optimized surface structure reduces the cutting friction coefficient, decreases chip adhesion, improves the tribological performance and chip evacuation efficiency during the cutting process, and enhances the machining surface quality. Description of the Drawings

[0026] Figure 1 It is a schematic flow chart of the preparation method of a high-strength wear-resistant cutting tool according to the present invention. Detailed Embodiments

[0027] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0028] Please refer to the attached Figure 1 , an embodiment of the present invention provides a high-strength wear-resistant cutting tool, including the following parts by weight: tungsten carbide nanopowder: 85 - 89.5 parts, cobalt powder: 9 - 12 parts, chromium carbide: 0.5 - 1 part, tantalum powder: 1 - 2 parts, molybdenum powder: 0 - 0.5 part, and the particle size range of the tungsten carbide nanopowder is 50 - 100 nm.

[0029] Specifically, the tungsten carbide nanopowder is used as the main component of the matrix, and its particle size range of 50 - 100 nm can ensure that the material has both high hardness and good toughness; the cobalt powder is used as the binder phase, optimizing the wettability and distribution uniformity of the hard phase; the chromium carbide effectively inhibits the abnormal growth of grains during sintering and maintains the stability of the nano-structure; the synergistic addition of tantalum powder and 0 - 0.5 part of molybdenum powder enables the tool to still maintain excellent red hardness during high-temperature cutting through solid solution strengthening and grain boundary purification effects, solving the problem that traditional tool materials are difficult to balance high hardness, high toughness and high-temperature stability, and improving the comprehensive performance of the tool.

[0030] Please refer to the attached Figure 1 , a preparation method of a high-strength wear-resistant cutting tool, the method includes the following steps:

[0031] S1. Weigh tungsten carbide nanopowder, cobalt powder, chromium carbide, tantalum powder, and molybdenum powder and mix them, then perform ball milling treatment, and then load them into a graphite mold and place them in a hot press sintering furnace to obtain a gradient matrix;

[0032] S2. Load the gradient matrix into a pulsed magnetron sputtering device, use a TiSi target, and perform bottom layer deposition;

[0033] S3. Then alternately use the AlCr target and the AlCrO target to deposit and form an AlCrON intermediate layer;

[0034] S4. Finally, transfer to a laser-assisted chemical vapor deposition equipment, use Al(CH3)3 + H2O as the precursor to deposit an α-Al2O3 coating, and finally form a preliminary tool;

[0035] S5. Then use a femtosecond laser processing system to machine the rake face of the tool to form a micro-pit array;

[0036] S6. Finally, place the tool in a vacuum impregnation equipment for impregnation and dry it using a drying oven.

[0037] Specifically, in step S1, by mixing tungsten carbide nanopowder, cobalt powder, chromium carbide, tantalum powder, and molybdenum powder and then performing ball milling, and placing it in a hot press sintering furnace, a gradient structure matrix with a dense surface layer and a strong and tough core can be obtained, improving the bending strength;

[0038] In step S2, by adopting the high-energy pulsed magnetron sputtering technology, the dense deposition of the TiSiN coating is realized under low-temperature conditions, solving the problem of poor bonding force caused by the mismatch of the thermal expansion coefficients of the coating and the matrix, and improving the interface bonding strength;

[0039] In step S3, through the AlCrN / AlCrO nano-multilayer structure design, a transition layer with a gradient change in oxygen content is formed, effectively alleviating the stress concentration inside the coating and improving the thermal shock resistance of the coating;

[0040] In step S4, through the laser-assisted CVD process in the laser-assisted chemical vapor deposition equipment, the low-temperature preferred orientation growth of the α-Al2O3 coating is realized, solving the problem of matrix performance deterioration caused by traditional high-temperature CVD, and enhancing the surface wear resistance;

[0041] In step S5, by using the femtosecond laser micro-texturing technology to precisely control the pit morphology, the problem of chip adhesion during the cutting process is solved, and the surface machining quality is improved;

[0042] In step S6, the vacuum impregnation process ensures the uniform filling and firm bonding of the solid lubricant in the micro-pits, forming a self-lubricating functional surface, reducing the friction coefficient of the tool under dry cutting conditions.

[0043] In S1, a three-dimensional mixer is used for mixing for 30 - 60 minutes, and a planetary ball mill is used for ball milling. Under argon protection, ball milling is carried out for 4 - 6 hours at a rotational speed of 200 - 300 r / min. After being placed in a hot press sintering furnace, it is heated to 1180 - 1220 °C at a rate of 8 - 12 °C / min under argon protection, an axial pressure of 45 - 55 MPa is applied and maintained for 4 - 6 minutes, and at the same time, an 8 - 12 kHz pulsed electromagnetic field is applied by an electromagnetic generating device to obtain a gradient matrix with a cobalt content of 5.5 - 6.5% on the surface layer and a cobalt content of 11.5 - 12.5% in the core part.

[0044] Specifically, mixing for 30 - 60 minutes by a three-dimensional mixer ensures the uniform dispersion of raw materials. Using a planetary ball mill to carry out ball milling for 4 - 6 hours at 200 - 300 r / min under argon protection realizes nanoscale uniform mixing. By heating to 1180 - 1220 °C at a rate of 8 - 12 °C / min under argon protection in a hot press sintering furnace and applying an axial pressure of 45 - 55 MPa and maintaining for 4 - 6 minutes, dense sintering is achieved. At the same time, an 8 - 12 kHz pulsed electromagnetic field is applied to precisely control the cobalt phase distribution. Finally, a gradient matrix with a cobalt content of 5.5 - 6.5% on the surface layer and a cobalt content of 11.5 - 12.5% in the core part is obtained, solving the problems of uneven component distribution, insufficient density, and uncontrollable cobalt phase distribution in the traditional sintering process, and enabling the matrix material to have the properties of high surface hardness and high core toughness at the same time.

[0045] In S2, the silicon content of the TiSi target is 7 - 9 at%, in an Ar / N2 mixed atmosphere with an N2 partial pressure of 0.3 - 0.5 Pa, the substrate temperature is controlled at 380 - 420 °C, the bias voltage is -90 - -110 V, and the deposition rate is 0.25 - 0.35 μm / h to form a 0.8 - 1.2 μm thick TiSiN bottom layer.

[0046] Specifically, by using a TiSi target with a silicon content of 7 - 9 at%, in an Ar / N2 mixed atmosphere, with the optimized parameter combination of controlling the substrate temperature at 380 - 420 °C, the bias voltage at -90 - -110 V, and the deposition rate at 0.25 - 0.35 μm / h, high-quality deposition of a 0.8 - 1.2 μm thick TiSiN bottom layer is achieved, enabling the TiSiN coating to form a dense nanocolumnar crystal structure, having excellent bonding strength and heat resistance, and providing a transition layer for the deposition of subsequent multi-layer coatings.

[0047] In S3, during deposition, the O2 partial pressure is controlled by a mass flow meter to gradually increase from an initial 0.08 - 0.12 Pa to 0.28 - 0.32 Pa, and [AlCrN(8 - 12 nm) / AlCrO(4 - 6 nm)] × 18 - 22 cycles are deposited, and the total thickness of the finally formed intermediate layer is 2.8 - 3.2 μm.

[0048] Specifically, the O2 partial pressure is accurately controlled by a mass flow meter to gradually increase from an initial 0.08-0.12 Pa to 0.28-0.32 Pa, and an alternating deposition method of [AlCrN (8-12 nm) / AlCrO (4-6 nm)] × 18-22 cycles is adopted to form a nano-multilayer structure intermediate layer with a total thickness of 2.8-3.2 μm. Through the gradient change of oxygen partial pressure and the periodic structure design at the nanoscale, the internal stress gradient of the coating is precisely controlled and the crack propagation is effectively hindered, so that the intermediate layer has excellent toughness and thermal stability, which solves the technical problem that traditional single-component coatings are prone to cracking and peeling under thermal cycling conditions.

[0049] In S4, when the α-Al2O3 surface layer is formed, the laser power is controlled to be 480-520W, the substrate temperature is 580-620°C, the deposition rate is 1.1-1.3μm / h, and the final thickness is 4.8-5.2μm.

[0050] Specifically, by controlling the synergistic parameter combination of laser power of 480-520W, substrate temperature of 580-620℃ and deposition rate of 1.1-1.3μm / h, the low-temperature preferential orientation growth of 4.8-5.2μm thick α-Al2O3 surface layer was achieved. Through laser-assisted chemical vapor deposition technology, the preferential formation of α-Al2O3 (012) crystal plane was promoted under relatively low temperature conditions, so that the surface layer obtained excellent wear resistance and chemical stability, while avoiding the damage to the mechanical properties of the substrate material by the traditional high-temperature CVD process.

[0051] In S5, the wavelength of the femtosecond laser processing system is 1060-1080nm, the pulse width is 100-150fs, the scanning speed is 190-210mm / s, and a micro-pit array with a diameter of 48-52μm, a depth of 14-16μm, and a spacing of 98-102μm is processed on the front face of the tool.

[0052] Specifically, by precisely controlling the parameter combination of laser wavelength of 1060-1080nm, pulse width of 100-150fs and scanning speed of 190-210mm / s, a regular micro-pit array with a diameter of 48-52μm, a depth of 14-16μm and a spacing of 98-102μm is machined on the front face of the tool. Through the cold processing characteristics of ultrashort pulse laser, precise preparation of micron-level surface texture is achieved, so that the tool surface has the dual functions of friction reduction and chip guidance, thereby improving the processing surface quality and tool life.

[0053] In S6, molybdenum disulfide powder with a particle size of 0.8 to 1.2 μm is impregnated under a vacuum degree of 1×10-3 to 5×10-3 Pa for 28 to 32 minutes, transferred into a drying oven, and cured at 80 to 100°C for 1 to 2 hours to finally obtain a finished tool.

[0054] Specifically, by using molybdenum disulfide powder with a particle size of 0.8 to 1.2 μm, impregnating it under high vacuum conditions of 1×10-3 to 5×10-3 Pa for 28 to 32 minutes, and curing it at 80 to 100°C for 1 to 2 hours, the solid lubricant is fully filled and firmly bonded in the micro-pits. The vacuum impregnation technology is used to ensure that the lubricant is evenly distributed on the surface of the microstructure, forming a tool working surface with a self-lubricating function, reducing the friction coefficient during the cutting process, lowering the cutting temperature, and extending the tool life.

[0055] Before S2, the substrate surface is bombarded with Ar ions at an energy of 50-80 eV and an incident angle of 45-60° to form an activation layer with a surface roughness of Ra0.2-0.3 μm.

[0056] Specifically, by using Ar ion bombardment treatment with an energy of 50-80eV and an incident angle of 45-60°, an activation layer of Ra0.2-0.3μm is formed on the substrate surface. By controlling the ion bombardment parameters, nanoscale cleaning and microscopic coarsening of the substrate surface are achieved, the surface activity is improved, and a uniformly distributed nanoscale concave-convex structure is formed, providing an ideal bonding interface for subsequent coating deposition.

[0057] In S5, dual-beam femtosecond laser processing is used, with the main beam energy density of 2-3J / cm 2 , auxiliary beam energy density 0.5-1.0J / cm 2 The angle between the two beams is 20-30°, forming a hemispherical pit with a bottom curvature radius of 20-25μm.

[0058] Specifically, the main beam energy density is 2-3J / cm 2 、Auxiliary beam energy density 0.5-1.0J / cm 2 The synergistic effect of the 20-30° angle between the two light beams enables precise hemispherical pit processing with a bottom curvature radius of 20-25μm. While the main beam is used to achieve precise material removal, the auxiliary beam is used to perform secondary trimming on the edge of the pit, which improves the regularity of the pit morphology and reduces the surface roughness. The lubricant storage capacity and chip diversion efficiency of the micro-pits are improved, providing the tool with better friction reduction and anti-sticking effects.

[0059] Example 1

[0060] Weigh 85 parts of 50nm tungsten carbide nanopowder, 9 parts of cobalt powder, 0.5 part of chromium carbide, 1 part of tantalum powder and 0 part of molybdenum powder as raw materials, mix them evenly through a three-dimensional mixer for 30 minutes, then under argon protection, use a planetary ball mill to ball mill at a speed of 200r / min for 4 hours to complete nanoscale mixing. After loading the mixed powder into a graphite mold, in a hot-pressing sintering furnace under argon protection, heat it to 1180℃ at a rate of 8℃ / min, apply an axial pressure of 45MPa and hold for 4 minutes, and at the same time apply an 8kHz pulsed electromagnetic field to finally obtain a gradient structure matrix with a surface cobalt content of 5.5% and a core cobalt content of 11.5%;

[0061] After that, use a TiSi target with a silicon content of 7at%, in an Ar / N2 mixed atmosphere with an N2 partial pressure of 0.3Pa, deposit a 0.8μm thick TiSiN bottom layer under the conditions of controlling the substrate temperature at 380℃, the bias voltage at -90V, and the deposition rate at 0.25μm / h. Subsequently, control the O2 partial pressure to gradually increase from the initial 0.08Pa to 0.28Pa through a mass flowmeter, and deposit [AlCrN(8nm) / AlCrO(4nm)]×18 cycles to form an AlCrON intermediate layer with a total thickness of 2.8μm. Finally, deposit a 4.8μm thick α-Al2O3 surface layer under the conditions of a laser power of 480W, a substrate temperature of 580℃, and a deposition rate of 1.1μm / h;

[0062] Finally, use a femtosecond laser with a wavelength of 1060nm and a pulse width of 100fs to scan the rake face at a speed of 190mm / s to process a micro-pit array with a diameter of 48μm, a depth of 14μm, and a pitch of 98μm. Subsequently, use molybdenum disulfide powder with a particle size of 0.8μm and impregnate it in a vacuum of 1×10-3Pa for 28 minutes, and finally dry and cure it at 80℃ for 1 hour to obtain the finished tool.

[0063] Example 2

[0064] Weigh 87.25 parts of 75nm tungsten carbide nanopowder, 10.5 parts of cobalt powder, 0.75 part of chromium carbide, 1.5 part of tantalum powder and 0.25 part of molybdenum powder as raw materials, mix them evenly through a three-dimensional mixer for 45 minutes, then under argon protection, use a planetary ball mill to ball mill at a speed of 250r / min for 5 hours to complete nanoscale mixing. After loading the mixed powder into a graphite mold, in a hot-pressing sintering furnace under argon protection, heat it to 1200℃ at a rate of 10℃ / min, apply an axial pressure of 50MPa and hold for 5 minutes, and at the same time apply a 10kHz pulsed electromagnetic field to finally obtain a gradient structure matrix with a surface cobalt content of 6.0% and a core cobalt content of 12.0%;

[0065] Subsequently, a TiSi target with a silicon content of 8 at% was used to deposit a 1.0-μm-thick TiSiN bottom layer under the conditions of a substrate temperature of 400 °C, a bias voltage of -100 V, and a deposition rate of 0.3 μm / h in an Ar / N2 mixed atmosphere with an N2 partial pressure of 0.4 Pa. Subsequently, the O2 partial pressure was gradually increased from an initial 0.10 Pa to 0.30 Pa through a mass flowmeter, and [AlCrN(10 nm) / AlCrO(5 nm)]×20 cycles were deposited to form an AlCrON intermediate layer with a total thickness of 3.0 μm. Finally, a 5.0-μm-thick α-Al2O3 surface layer was deposited under the conditions of a laser power of 500 W, a substrate temperature of 600 °C, and a deposition rate of 1.2 μm / h;

[0066] Finally, a femtosecond laser with a wavelength of 1070 nm and a pulse width of 125 fs was used to machine a micro-pit array with a diameter of 50 μm, a depth of 15 μm, and a pitch of 100 μm on the rake face at a scanning speed of 200 mm / s. Subsequently, molybdenum disulfide powder with a particle size of 1.0 μm was used, and it was impregnated for 30 minutes under a vacuum of 3×10 -3 Pa, and finally dried and cured at 90 °C for 1.5 hours to obtain the finished tool.

[0067] Example 3

[0068] 89.5 parts of 100-nm tungsten carbide nanopowder, 12 parts of cobalt powder, 1 part of chromium carbide, 2 parts of tantalum powder, and 0.5 part of molybdenum powder were weighed as raw materials and uniformly dispersed by mixing in a three-dimensional mixer for 60 minutes. Subsequently, under argon protection, a planetary ball mill was used to ball mill at a rotation speed of 300 r / min for 6 hours to complete the nano-level mixing. After loading the mixed powder into a graphite mold, it was heated to 1220 °C at a rate of 12 °C / min in a hot press sintering furnace under argon protection, an axial pressure of 55 MPa was applied and maintained for 6 minutes, and at the same time, a 12-kHz pulsed electromagnetic field was applied, and finally a gradient structure substrate with a cobalt content of 6.5% on the surface layer and 12.5% in the core was obtained;

[0069] Subsequently, a TiSi target with a silicon content of 9 at% was used to deposit a 1.2-μm-thick TiSiN bottom layer under the conditions of a substrate temperature of 420 °C, a bias voltage of -110 V, and a deposition rate of 0.35 μm / h in an Ar / N2 mixed atmosphere with an N2 partial pressure of 0.5 Pa. Subsequently, the O2 partial pressure was gradually increased from an initial 0.12 Pa to 0.32 Pa through a mass flowmeter, and [AlCrN(12 nm) / AlCrO(6 nm)]×22 cycles were deposited to form an AlCrON intermediate layer with a total thickness of 3.2 μm. Finally, a 5.2-μm-thick α-Al2O3 surface layer was deposited under the conditions of a laser power of 520 W, a substrate temperature of 620 °C, and a deposition rate of 1.3 μm / h;

[0070] Finally, a femtosecond laser with a wavelength of 1080 nm and a pulse width of 150 fs was used to scan the rake face at a speed of 210 mm / s to machine a micro-pit array with a diameter of 52 μm, a depth of 16 μm, and a pitch of 102 μm. Subsequently, molybdenum disulfide powder with a particle size of 1.2 μm was used to impregnate for 32 minutes under a vacuum of 5×10-3 Pa, and finally dried and cured at 100 °C for 2 hours to obtain the finished tool.

[0071] Comparative example

[0072] 92 parts of 1 μm tungsten carbide micro-powder and 8 parts of cobalt powder were mixed, mechanically stirred for 1 hour, and then ball-milled at 400 r / min for 10 hours in an unprotected atmosphere. After the mixed powder was molded by die pressing, it was kept at 1350 °C for 2 hours in an atmospheric pressure sintering furnace to obtain a homogeneous matrix (cobalt content 8%). A 3-μm-thick TiN single-layer coating was prepared on the surface of the matrix by arc evaporation deposition process, without intermediate transition layer deposition and surface texturing treatment.

[0073] Experimental table

[0074]

[0075] Through the comparison of the above data, the preparation method of the high-strength wear-resistant cutting tool can improve the surface and core hardness, enhance the bending resistance and toughness, and extend the service life.

[0076] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-strength wear-resistant cutting tool, characterized in that: The invention comprises the following parts by weight: 85 to 89.5 parts of tungsten carbide nano powder, 9 to 12 parts of cobalt powder, 0.5 to 1 part of chromium carbide, 1 to 2 parts of tantalum powder and 0 to 0.5 part of molybdenum powder. The particle size of the tungsten carbide nano powder is in the range of 50 to 100 nm.

2. A method for preparing a high-strength wear-resistant cutting tool, characterized in that: For a high-strength wear-resistant cutting tool as claimed in claim 1, the method comprises the following steps: S1. Weigh tungsten carbide nanopowder, cobalt powder, chromium carbide, tantalum powder and molybdenum powder, mix them, and then ball-mill them. Then, put them into a graphite mold and place them in a hot pressing sintering furnace to obtain a gradient matrix. S2, loading the gradient substrate into a pulsed magnetron sputtering device, using a TiSi target material, to perform bottom layer deposition; S3, then using the AlCr target and the AlCrO target alternately to deposit and form an AlCrON intermediate layer; S4, finally transferred to the laser-assisted chemical vapor deposition equipment, using Al(CH3)3+H2O as a precursor, α-Al2O3 coating, and finally forming a preliminary tool; S5, then a femtosecond laser processing system is used to process the front face of the tool to form a micro-pit array; S6. Finally, the tool is placed in a vacuum impregnation device for impregnation and dried in a drying oven.

3. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: In the S1, a three-dimensional mixer is used for mixing for 30 to 60 minutes, a planetary ball mill is used for ball milling under argon protection for 4 to 6 hours at a rotation speed of 200 to 300 r / min, and after being placed in a hot pressing sintering furnace, the temperature is raised to 1180 to 1220° C. at a rate of 8 to 12° C. / min under argon protection, an axial pressure of 45 to 55 MPa is applied and maintained for 4 to 6 minutes, and an electromagnetic generator is used to apply a pulsed electromagnetic field of 8 to 12 kHz to obtain a gradient matrix with a surface cobalt content of 5.5 to 6.5% and a core cobalt content of 11.5 to 12.5%.

4. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: In the S2, the silicon content of the TiSi target is 7-9at%, and in an Ar / N2 mixed atmosphere, a N2 partial pressure of 0.3-0.5Pa, the substrate temperature is controlled at 380-420°C, the bias voltage is -90--110V, and the deposition rate is 0.25-0.35μm / h to form a 0.8-1.2μm thick TiSiN bottom layer.

5. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: In S3, during deposition, the O2 partial pressure is controlled by a mass flow meter to gradually increase from an initial 0.08-0.12 Pa to 0.28-0.32 Pa, and [AlCrN (8-12 nm) / AlCrO (4-6 nm)] is deposited for 18-22 cycles, and the total thickness of the intermediate layer finally formed is 2.8-3.2 μm.

6. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: In the above S4, when forming the α-Al2O3 surface layer, the laser power is controlled to be 480-520W, the substrate temperature is 580-620°C, the deposition rate is 1.1-1.3 μm / h, and the final thickness is 4.8-5.2 μm.

7. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: In S5, the wavelength of the femtosecond laser processing system is 1060-1080nm, the pulse width is 100-150fs, the scanning speed is 190-210mm / s, and a micro-pit array with a diameter of 48-52μm, a depth of 14-16μm, and a spacing of 98-102μm is processed on the front face of the tool.

8. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: In the above S6, molybdenum disulfide powder with a particle size of 0.8 to 1.2 μm is impregnated in a vacuum of 1×10 -3 ~5×10 -3 The cutting tool is immersed in the mixture under Pa conditions for 28 to 32 minutes, and then transferred into a drying oven and cured at 80 to 100° C. for 1 to 2 hours to finally obtain a finished cutting tool.

9. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: Before the step S2, the substrate surface is bombarded with Ar ions at an energy of 50-80 eV and an incident angle of 45-60° to form an activation layer with a surface roughness of Ra 0.2-0.3 μm.

10. The method for preparing a high-strength wear-resistant cutting tool according to claim 2, characterized in that: In S5, dual-beam femtosecond laser processing is used, and the main beam energy density is 2-3J / cm 2 , auxiliary beam energy density 0.5-1.0J / cm 2 The angle between the two beams is 20-30°, forming a hemispherical pit with a bottom curvature radius of 20-25μm.

Images