Multi-region gradient hard alloy material and preparation method thereof

Abstract

The invention provides a multi-zone gradient hard alloy material, and relates to the field of hard alloy materials, the multi-zone gradient hard alloy material comprises a drill tip zone, a transition zone and a drill handle zone from the outer layer to the inner layer, the drill tip zone comprises AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C, the transition zone comprises WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, and the drill handle zone comprises WC, Co, Ni and ZrC. Through gradient structure design, interface stress concentration in the sintering process is effectively reduced, the hardness and wear resistance of the material are improved, so that the overall crack resistance and service stability of the structure are improved, the service life of the structure is prolonged, and the material is suitable for the field of complex impact loads such as mine drilling and geological survey.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cemented carbide material, and particularly relates to a multi-region gradient cemented carbide material and a preparation method thereof. BACKGROUND

[0002] The cemented carbide drill bit is a high-performance drilling tool mainly composed of tungsten carbide (WC) and cobalt (Co) as a binder, and is manufactured through a powder metallurgy process. The cemented carbide drill bit has high hardness (HRA 89-93), excellent wear resistance and thermal stability, and is widely used in the fields of mechanical manufacturing, aerospace, mine drilling and geological exploration. However, under the conditions of mine drilling and geological exploration, due to uneven strata (i.e., alternating appearance of quartz particles in hard rock and argillaceous interlayer in soft rock, resulting in sudden change of cutting resistance), poor chip removal (for example, rock powder is accumulated at the bottom of the hole, and when the rock powder is extruded, the reaction force impacts the drill bit, causing “secondary impact”), and dynamic response lag of equipment, the cemented carbide drill bit is subjected to complex impact load (including impact stress peak value far exceeding the bending strength limit of ordinary cemented carbide, alternating stress caused by alternating strata of hard interlayer and soft rock layer, and three-dimensional composite stress field formed by axial impact, radial vibration and circumferential torque fluctuation). The traditional double-layer composite structure of the cemented carbide drill bit is prone to interface stress concentration due to composition mutation, which not only increases the risk of crack propagation and fracture, reduces the service life and reliability of the drill bit, but also easily causes deformation of the drill bit, leading to sticking of the drill bit, thereby reducing the drilling and exploration efficiency, and even causing safety hazards in the drilling and exploration process. SUMMARY

[0003] In view of the problems in the prior art, the present application aims to provide a multi-region gradient cemented carbide material. The material is designed with a gradient structure, which effectively reduces the interface stress concentration in the sintering process and improves the hardness and wear resistance of the material, thereby improving the crack resistance, service stability and service life of the overall structure, and is suitable for fields with complex impact load such as mine drilling and geological exploration.

[0004] Another object of the present application is to provide a preparation method of the multi-region gradient cemented carbide material.

[0005] The object of the present application is achieved by the following technical solutions. A multi-region gradient cemented carbide material comprises a drill tip region, a transition region and a drill shank region from the outer layer (i.e., the front end of the drill bit) to the inner layer (i.e., the rear end). The drill tip region comprises AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C. The transition region comprises WC, Co, ZrC, nano-particles, NbC and carbon nanotubes. The drill shank region comprises WC, Co, Ni and ZrC. The drill tip region comprises AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C. The transition region comprises WC, Co, ZrC, nano-particles, NbC and carbon nanotubes. The drill shank region comprises WC, Co, Ni and ZrC.

[0006] Further optimization based on the above scheme, the drill tip area thickness is 0.3 μm to 0.9 μm, the transition zone thickness is 0.3 μm to 1.0 μm, the drill handle area thickness is 0.9 μm to 3.0 μm.

[0007] Further optimization based on the above scheme, the content of each component (i.e. AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) in the drill tip area is: 3-5wt%, 88-92wt%, 1-2wt%, 2.5-3.5wt%, 0.3-0.7wt%, TaC is arranged on the side of the drill tip area close to the transition zone, and the thickness is 40-60 μm; wherein the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2 μm; the particle size of SiC-B4C composite particles is 0.1-0.3 μm, and the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of TaC powder is 50-100 nm; the particle size of Mo2C powder is 0.1-0.3 μm.

[0008] Further optimization based on the above scheme, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) in the transition zone is: 75-79wt%, 14-18wt%, 3-5wt%, 2-3wt%, 0.4-0.6wt%, NbC is arranged on the side of the transition zone close to the drill tip area, and the thickness is 40-60 μm; wherein the powder particle size of WC, Co, ZrC is 0.5-1.0 μm; the particle size of the particles is 50-80 nm; the particle size of the NbC powder is 50-100 nm; the length of the carbon nanotube is 5-10 μm.

[0009] Further optimization based on the above scheme, the content of each component (i.e. WC, Co, Ni and ZrC) in the drill handle area is: 65-69wt%, 24-28wt%, 3-4wt%, 3-4wt%; wherein the powder particle size of WC, Co, Ni, ZrC is 2-5 μm.

[0010] A preparation method of a multi-region gradient cemented carbide material, comprising: Step S1, drill tip area preparation: first, the components of the drill tip area are proportioned, and SiC-B4C composite particles and TaC powder are pretreated; then, in a high-energy planetary grinding machine under inert gas protection, the grinding ball is a WC-Co alloy ball with a diameter of 5 mm, the dispersion medium is anhydrous ethanol and oleic acid, TiCN, ZrC and Mo2C are first ball milled, then AlTiN and SiC-B4C composite particles are added, ultrasonic dispersion is performed, and then ball milling is performed; the slurry after ball milling is vacuum dried to obtain a drill tip area preliminary powder; Step S2, transition zone preparation: first, prepare (W, Zr)C solid solution powder in proportion; then mix part of (W, Zr)C solid solution powder, Co powder and carbon nanotubes to generate in-situ adsorbed carbon nanotubes nanoparticles; then, add Co powder and the remaining (W, Zr)C solid solution powder, and mix in an argon atmosphere; after vacuum drying, reduce in a tube furnace by passing hydrogen gas; after reduction, vacuum ball mill and spray dry to obtain transition zone preparation powder; Step S3, shank zone preparation: use gas atomization to melt Co powder and Ni powder in proportion to obtain Co-Ni pre-alloy powder; mix (W, Zr)C solid solution powder prepared in proportion with Co-Ni pre-alloy powder, add grain inhibitors in ethanol as medium, and mix in an argon atmosphere; after vacuum drying, reduce in a tube furnace by passing hydrogen gas; after reduction, vacuum ball mill and spray dry to obtain shank zone preparation powder; Step S4, material forming: layer by layer press the shank zone preparation powder, transition zone preparation powder and drill tip zone preparation powder in order of shank zone, transition zone and drill tip zone; during layer by layer pressing, lay NbC layer and TaC layer on the surface of the transition zone away from the shank zone; finally, perform gradient hot isostatic pressing diffusion in a nitrogen atmosphere to obtain a cemented carbide material.

[0011] Based on further optimization of the above scheme, the specific method for "pretreating SiC-B4C composite particles and TaC powder" in step S1 is: surface modification of milled SiC-B4C composite particles with silane coupling agent (KH550), the silane coupling agent accounting for 0.8-1.2wt% of SiC-B4C composite particles; vacuum drying TaC powder at a temperature of 110-130℃ for 1.5-2.5h.

[0012] Based on further optimization of the above scheme, the rotation speed for first adding TiCN, ZrC and Mo2C for ball milling in step S1 is 280-320rpm for 0.8-1.2h; the rotation speed for adding AlTiN and SiC-B4C composite particles for ball milling is 380-420rpm for 1.8-2.2h, and the frequency for ultrasonic dispersion is 18-22kHz for 28-32min.

[0013] Based on the further optimization of the above scheme, the preparation process of the (W, Zr)C solid solution powder in the step S2 and step S3 is as follows: tungsten powder, zirconium powder and graphite powder are weighed respectively, rare earth element oxide is added, then the raw materials and tungsten carbide balls are loaded into a stainless steel vacuum ball mill pot for high-energy ball milling, the ball milling speed is 480-520 rpm, and the time is 7.5-8.5 h; then the ball-milled product is placed in a high-temperature atmosphere furnace, and a thermal combination reaction is carried out at a temperature of 800-900℃ under a nitrogen-hydrogen mixed gas atmosphere (the volume ratio of nitrogen to hydrogen is 5-10:1-2), and the reaction time is 1.5-2.5 h, to obtain the (W, Zr)C solid solution powder.

[0014] Based on the further optimization of the above scheme, the rare earth element is any one of La, Ce, Pr, Nd, Pm, Sm and Eu.

[0015] Based on the further optimization of the above scheme, the surface-adsorbed carbon nanotube generated in situ in the step S2 is prepared by the following steps: The nanoparticles are prepared by mixing part of the (W, Zr)C solid solution powder with Co powder according to the atomic ratio (i.e. Co:W=1:1), adding nano-tungsten powder (particle size about 50 nm) and carbon nanotubes, and ball milling in an argon atmosphere to obtain a precursor; the precursor is placed in a tube furnace, hydrogen is introduced into the tube furnace, and heating is performed to generate the surface-adsorbed carbon nanotube nanoparticles.

[0016] Based on the further optimization of the above scheme, the ball milling speed for preparing the precursor in the step is 280-320 rpm, and the time is 3.5-4.5 h; the heating temperature for reduction when hydrogen is introduced into the tube furnace is 830-870℃, and the holding time is 1.8-2.2 h.

[0017] Based on the further optimization of the above scheme, the Co-Ni pre-alloy powder prepared by the gas atomization method in the step S3 is prepared by melting Co powder and Ni powder at a ratio at 1550-1650℃, and then using argon gas atomization to prepare a pre-alloy powder with a particle size of 2-5 μm under a pressure of 0.45-0.55 MPa.

[0018] Based on the further optimization of the above scheme, the grain inhibitor used in the step S3 is VC, and the content is 0.3 wt%.

[0019] Based on the further optimization of the above scheme, the layering pressing in the step S4 is pre-pressed by cold isostatic pressing, the pressing pressure is 250-300 MPa, and the time is 8-12 min.

[0020] ​​Based on further optimization of the above scheme, the gradient hot isostatic pressing diffusion in the step S4 is specifically: first, at 1080-1120 DEG C, 90-110 MPa, holding for 0.9-1.1 h; then at 1330-1370 DEG C, 115-135 MPa, holding for 1.9-2.1 h; finally at 1380-1420 DEG C, 140-160 MPa, holding for 1.9-2.1 h.

[0021] The following are the technical effects possessed by the present scheme: The present application cooperates the drill tip area composed of AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C with the transition area composed of WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, firstly, the glass phase generated by the SiC-B4C composite particles is used for crack filling and crack propagation inhibition to form self-repair, avoid the aging acceleration of the hard alloy under complex impact load and the problems of cracks or delamination caused by the chemical bond difference of each component in the drill tip area, and at the same time, the hard and brittle phase formed between the composite particles and AlTiN, TiCN is used for synergy and enhancement of the overall hardness of the material surface (hardness≥95HRA); secondly, the in-situ generated nanoparticles form a grain boundary pinning phase, which not only inhibits grain growth, maintains the fine grain structure of the transition area, avoids the agglomeration between powders, but also effectively inhibits the decomposition of nanoparticles at high temperature and improves the overall bending strength of the material (bending strength≥3600MPa); thirdly, the solid solution formed by TaC and NbC under hot isostatic pressing diffusion, not only uses the solid solution to pin the grain boundary migration and "bridge" the interface on both sides to relieve the interface stress concentration and enhance the bonding strength between the drill tip area and the transition area, but also effectively avoids the diffusion of elements (such as Ti and Al) in the drill tip area to the transition area and the diffusion of elements (such as Co) in the transition area to the drill tip area, ensuring the strength and toughness of the overall hard alloy material; fourthly, the cooperation between the plastic phase Mo2C and TaC, NbC not only pins the grain boundary at the same time, but also effectively buffers the interface thermal stress, further improves the interface bonding strength, avoids the problems of cracks, fractures or delaminations between the drill tip area (TiCN with a thermal expansion coefficient of 7-8x10 -6 / K) and the transition area (WC-based with a thermal expansion coefficient of 5-6x10 -6 / K) due to the large difference in expansion coefficient. In addition, through the three-layer structure setting of the drill tip area, the transition area and the shank area, not only the bonding strength between the layers is improved through the cooperation of the transition area (the gradient composition design of the transition area and the shank area ensures the bonding strength), but also the hard alloy has high fracture toughness (fracture toughness≥21MPa·m 1 / 2 ), ensuring the service life and reliability of the drill bit. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A schematic view of the cemented carbide material in the embodiments of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0024] Embodiment 1: A multi-region gradient cemented carbide material, from an outer layer (i.e. the front end of the drill bit) to an inner layer (i.e. the rear end), includes a drill tip region, a transition region and a shank region, the thickness of the drill tip region is 0.3 μm, the thickness of the transition region is 0.3 μm, and the thickness of the shank region is 0.9 μm. The composition of the drill tip region includes AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C, the content of each component (i.e. AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) is 3wt%, 92wt%, 1wt%, 3.5wt% and 0.5wt% in turn; TaC is arranged on the side of the drill tip region close to the transition region, and the thickness is 40 μm; wherein the powder particle size of AlTiN, TiCN and ZrC is 0.1-0.2 μm; the particle size of SiC-B4C composite particles is 0.1-0.3 μm, and the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of TaC powder is 50-100 nm; and the particle size of Mo2C powder is 0.1-0.3 μm. The composition of the transition region includes WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) is 75wt%, 18wt%, 5wt%, 1.6wt% and 0.4wt% in turn; NbC is arranged on the side of the transition region close to the drill tip region, and the thickness is 40 μm; wherein the powder particle size of WC, Co and ZrC is 0.5-1.0 μm; the particle size of nanoparticles is 50-80 nm; the particle size of NbC powder is 50-100 nm; and the length of carbon nanotubes is 5-10 μm. The composition of the shank region includes WC, Co, Ni and ZrC, the content of each component (i.e. WC, Co, Ni and ZrC) is 65wt%, 28wt%, 4wt% and 3wt% in turn; wherein the powder particle size of WC, Co, Ni and ZrC is 2-5 μm.

[0025] A preparation method of a multi-region gradient cemented carbide material, comprising: ​​​Step S1, drill tip region preparation: first, the components of the drill tip region are proportioned, and the SiC-B4C composite particles and TaC powder are pretreated; specifically: the SiC-B4C composite particles (i.e., SiC particles and B4C particles are mixed and ball milled at a mass ratio of 1:1 to obtain SiC-B4C composite particles with a particle size of 0.1-0.3 μm) after ball milling are surface modified with a silane coupling agent (KH550), and the silane coupling agent accounts for 0.8 wt% of the SiC-B4C composite particles (enhancing wettability); the TaC powder is vacuum dried at a temperature of 110°C for 2.5 h (to remove adsorbed water and avoid the formation of pores during the sintering process).

[0026] Then, in a high-energy planetary mill under the protection of an inert gas (such as argon), the ball-to-material ratio is 10:1, the grinding balls are WC-Co alloy balls with a diameter of 5 mm, the dispersion medium is anhydrous ethanol (solid-to-liquid ratio 1:1.2) and oleic acid (amount 0.3 wt%), TiCN, ZrC, and Mo2C are first ball milled, the ball milling speed is 280 rpm, and the time is 1.2 h; then AlTiN and SiC-B4C composite particles are added, ultrasonic dispersion is performed, the ultrasonic dispersion frequency is 18 kHz, the time is 32 min, the rotation speed is 380 rpm, and the time is 2.2 h; the slurry after ball milling is vacuum dried (vacuum drying temperature is 100°C, time is 2.5 h), and the drill tip region preliminary powder is obtained.

[0027] Step S2, transition region preparation: first, the (W, Zr)C solid solution powder is prepared according to the proportions, specifically: tungsten powder, zirconium powder, and graphite powder are weighed according to the mass ratio of WC and ZrC in the transition region, rare earth oxides are added, and the rare earth element is La, then the raw materials and tungsten carbide balls are loaded into a stainless steel vacuum ball mill jar for high-energy ball milling (ball-to-material ratio is 8:1), the ball milling speed is 480 rpm, and the time is 8.5 h; then the ball-milled product is placed in a high-temperature atmosphere furnace, and a thermal combination reaction is carried out at a temperature of 800°C under a nitrogen-hydrogen mixed gas atmosphere (volume ratio of nitrogen to hydrogen is 5:1), and the reaction time is 2.5 h, to obtain the (W, Zr)C solid solution powder.

[0028] Then, part of the (W, Zr)C solid solution powder (the amount of W element in the (W, Zr)C solid solution powder here is consistent with the content of W element in the nanoparticles) and Co powder are mixed according to a mass ratio of 1:1, and the mixture is vacuum dried at a temperature of 100°C for 2.5 h to obtain the transition region preliminary powder. (W, Zr)C solid solution powder is prepared according to the mass ratio of WC to ZrC, and the prepared (W, Zr)C solid solution powder is mixed with Co-Ni pre-alloy powder in an argon atmosphere, with ethanol as a medium and with VC as a grain inhibitor, at a ball-to-powder ratio of 8:1, a ball milling speed of 180 rpm, and a ball milling time of 2.2 h. The mixed powder is vacuum dried (at a vacuum drying temperature of 100 DEG C for 2.5 h), and is reduced in a tube furnace with hydrogen gas (at a hydrogen gas flow rate of 8 L / min, at a holding temperature of 600 DEG C, and for a holding time of 2.5 h). After reduction, the powder is vacuum ball milled (at a ball milling speed of 180 rpm for 2.2 h), and is spray dried (using a conventional spray drying method), to obtain a drill shank zone pre-prepared powder. The heating temperature is 830 DEG C, and the holding time is 2.2 h.

[0029] Then, Co powder and the remaining (W, Zr)C solid solution powder are added, and are mixed and ball milled in an argon atmosphere, at a ball milling speed of 280 rpm and for a ball milling time of 3 h. The mixed powder is vacuum dried (at a vacuum drying temperature of 100 DEG C for 2.5 h), and is reduced in a tube furnace with hydrogen gas (at a hydrogen gas flow rate of 8 L / min, at a holding temperature of 600 DEG C, and for a holding time of 2.5 h). After reduction, the powder is vacuum ball milled (at a ball milling speed of 280 rpm for 3 h), and is spray dried (using a conventional spray drying method), to obtain a transition zone pre-prepared powder. Step S3, drill shank zone preparation: Co powder and Ni powder are melted according to a proportion, to obtain Co-Ni pre-alloy powder. Specifically, Co powder and Ni powder are melted at 1550 DEG C, and are argon gas atomized at a pressure of 0.45 MPa, to obtain pre-alloy powder with a particle size of 2-5 μm. Meanwhile, (W, Zr)C solid solution powder is prepared according to the mass ratio of WC to ZrC (the preparation method is the same as that in step S2).

[0030] (W, Zr)C solid solution powder prepared by mixing according to a proportion and Co-Ni pre-alloy powder are mixed and ball milled in an argon atmosphere, with ethanol as a medium and with VC as a grain inhibitor, at a ball-to-powder ratio of 8:1, a ball milling speed of 180 rpm, and a ball milling time of 2.2 h. The mixed powder is vacuum dried (at a vacuum drying temperature of 100 DEG C for 2.5 h), and is reduced in a tube furnace with hydrogen gas (at a hydrogen gas flow rate of 8 L / min, at a holding temperature of 600 DEG C, and for a holding time of 2.5 h). After reduction, the powder is vacuum ball milled (at a ball milling speed of 180 rpm for 2.2 h), and is spray dried (using a conventional spray drying method), to obtain a drill shank zone pre-prepared powder.

[0031] Step S4, material forming: the drill shank area, transition area, drill tip area in order to drill shank area, transition area, drill tip area preparatory powder layering pressing, layering pressing process, transition area away from the drill shank area on the side surface in turn laying NbC layer and TaC layer (i.e. first pressing drill shank area, then pressing transition, then laying NbC layer and TaC layer in turn, finally pressing drill tip area); layering pressing using cold isostatic pressing pre-pressing, pressing pressure is 250 MPa, time is 12 min.

[0032] Finally in nitrogen atmosphere, gradient hot isostatic pressing diffusion, specifically: first at 1080℃, 90 MPa, 1.1 h; then at 1330℃, 115 MPa, 2.1 h; finally at 1380℃, 140 MPa, 2.1 h; obtain cemented carbide material.

[0033] Example 2: A multi-region gradient cemented carbide material, from the outer layer (i.e. drill bit front end) to the inner layer (i.e. rear end) includes drill tip area, transition area and drill shank area, drill tip area thickness is 0.6 μm, transition area thickness is 0.6 μm, drill shank area thickness is 2.0 μm. Drill tip area composition includes AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C, the content of each component (i.e. AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) is: 4wt%, 90wt%, 1.5wt%, 3wt%, 0.5wt%, TaC is set on the side of the drill tip area close to the transition area, thickness is 50 μm; wherein, the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2 μm; the particle size of SiC-B4C composite particles is 0.1-0.3 μm, the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of TaC powder is 50-100 nm; the particle size of Mo2C powder is 0.1-0.3 μm. Transition area composition includes WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) is: 77wt%, 16wt%, 4wt%, 2.5wt%, 0.5wt%, NbC is set on the side of the transition area close to the drill tip area, thickness is 50 μm; wherein, the powder particle size of WC, Co, ZrC is 0.5-1.0 μm; The particle size of the particles is 50-80 nm; the particle size of the NbC powder is 50-100 nm; and the length of the carbon nanotube is 5-10 μm. The shank area composition comprises WC, Co, Ni and ZrC, and the content of each component (i.e. WC, Co, Ni and ZrC) is 67 wt%, 26 wt%, 3.5 wt% and 3.5 wt% respectively; wherein the powder particle size of WC, Co, Ni and ZrC is 2-5 μm.

[0034] A preparation method of a multi-zone gradient cemented carbide material, comprising: In step S1, the drill tip area is prepared as follows: first, the components of the drill tip area are proportioned, and SiC-B4C composite particles and TaC powder are pretreated; specifically, the SiC-B4C composite particles (i.e. SiC particles and B4C particles are mixed and ball milled at a mass ratio of 1:1 to obtain SiC-B4C composite particles with a particle size of 0.1-0.3 μm) are surface modified by using a silane coupling agent (KH550), and the silane coupling agent accounts for 1 wt% of the SiC-B4C composite particles (to enhance wettability); and the TaC powder is vacuum dried at a temperature of 120°C for 2 h (to remove adsorbed water and avoid the formation of pores during sintering).

[0035] Then, in a high-energy planetary ball mill under the protection of an inert gas (such as argon), the ball-to-material ratio is 10:1, the grinding balls are WC-Co alloy balls with a diameter of 5 mm, the dispersion medium is anhydrous ethanol (solid-liquid ratio 1:1.2) and oleic acid (amount 0.3 wt%), TiCN, ZrC and Mo2C are first ball milled, the ball milling speed is 300 rpm and the time is 1 h; then AlTiN and SiC-B4C composite particles are ball milled after ultrasonic dispersion, the ultrasonic dispersion frequency is 20 kHz and the time is 30 min, the ball milling speed is 400 rpm and the time is 2 h; and the ball milled slurry is vacuum dried (vacuum drying temperature 110°C, time 2 h) to obtain the drill tip area preliminary powder.

[0036] In step S2, the transition area is prepared as follows: first, the (W, Zr)C solid solution powder is prepared in proportion, specifically, tungsten powder, zirconium powder and graphite powder are weighed according to the mass ratio of WC and ZrC in the transition area, rare earth oxides are added, the rare earth element is Ce, then the raw materials and tungsten carbide balls are loaded into a stainless steel vacuum ball mill pot for high-energy ball milling (ball-to-material ratio 8:1), the ball milling speed is 500 rpm and the time is 8 h; then the ball milled product is placed in a high temperature atmosphere furnace, and a thermal combination reaction is carried out at a temperature of 850°C for 2 h in an atmosphere of a nitrogen-hydrogen mixed gas (volume ratio of nitrogen to hydrogen 7:1.5) to obtain the (W, Zr)C solid solution powder.

[0037] Then part of the (W, Zr) C solid solution powder (the amount of W element in the (W, Zr) C solid solution powder here is the same as The W content in the nanoparticles is consistent with that in the Co powder. The precursor was obtained by mixing the precursor with an atomic ratio of Co:W (i.e., Co:W=1:1), adding nano-tungsten powder (particle size of about 50nm, the atomic ratio of nano-tungsten powder to cobalt powder is 1:1, used to supplement tungsten) and carbon nanotubes, and ball milling was carried out in an argon atmosphere at a ball milling speed of 300rpm for 4 hours. The precursor was placed in a tubular furnace, and hydrogen (hydrogen flow rate 6L / min) was introduced into the tubular furnace to heat the precursor to generate carbon nanotubes adsorbed on the surface. Nanoparticles, heating temperature is 850℃, and holding time is 2h.

[0038] Then, Co powder and the remaining (W, Zr)C solid solution powder were added and mixed by ball milling in an argon atmosphere at a ball milling speed of 300 rpm for 2.5 hours. The mixed powder was vacuum dried (vacuum drying temperature of 110°C for 2 hours) and reduced again by hydrogen in a tube furnace (hydrogen flow rate of 8 L / min, holding time of 700°C for 2 hours). After reduction, it was vacuum ball milled (ball milling speed of 300 rpm for 2.5 hours) and spray dried (conventional spray drying method can be used) to obtain a transition zone preparatory powder. Step S3, Preparation of the Drill Shank: Using a gas atomization method, Co powder and Ni powder are melted in a proportional manner to obtain a Co-Ni pre-alloyed powder. Specifically, the Co powder and Ni powder are melted in a proportional manner at 1600°C, then atomized using argon gas at a pressure of 0.5 MPa to produce a pre-alloyed powder with a particle size of 2-5 μm. Simultaneously, a (W, Zr)C solid solution powder is prepared according to the mass ratio of WC to ZrC in the drill shank region (preparation method step S2).

[0039] The (W, Zr) C solid solution powder and Co-Ni pre-alloyed powder prepared by mixing in proportion are added with ethanol as the medium, and a grain inhibitor is used. The grain inhibitor is VC with a content of 0.3wt%. The mixed powder is ball-milled in an argon atmosphere with a ball-to-material ratio of 8:1, a ball milling speed of 200 rpm, and a ball milling time of 2 h. The mixed powder is vacuum dried (vacuum drying temperature is 110°C, time is 2 h), and reduced in a tube furnace with hydrogen (hydrogen flow rate is 8 L / min, holding time is 700°C, holding time is 2 h). After reduction, it is vacuum ball milled (ball milling speed is 200 rpm, time is 2 h), and spray dried (conventional spray drying method can be used) to obtain the drill shank area preparation powder.

[0040] Step S4, material forming: the drill shank area, transition area, drill tip area in order to drill shank area, transition area, drill tip area of the preparation of powder layering pressing, layering pressing process, transition area away from the drill shank area, one side surface of NbC layer and TaC layer (i.e. first pressing drill shank area, then pressing transition, then NbC layer and TaC layer, finally pressing drill tip area) ; Layering pressing using cold isostatic pressing pre-pressing, pressing pressure is 275 MPa, time is 10 min.

[0041] Finally, under nitrogen atmosphere, gradient hot isostatic pressing diffusion, specifically: first at 1100 DEG C, 100 MPa, 1 h; Then at 1350 DEG C, 125 MPa, 2 h; Finally at 1400 DEG C, 150 MPa, 2 h; Obtain the hard alloy material.

[0042] Example 3: A multi-region gradient hard alloy material, from the outer layer (i.e. drill bit front end) to the inner layer (i.e. rear end) includes drill tip area, transition area and drill shank area, drill tip area thickness is 0.9 μm, transition area thickness is 1.0 μm, drill shank area thickness is 3.0 μm. Drill tip area composition includes AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C, the content of each component (i.e. AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) is: 5wt%, 89wt%, 2wt%, 3.3wt%, 0.7wt%, TaC is set on the side of the drill tip area close to the transition area, the thickness is 60 μm; Among them, the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2 μm; The particle size of SiC-B4C composite particles is 0.1-0.3 μm, the mass ratio of SiC to B4C in the composite particles is 1:1; The particle size of TaC powder is 50-100 nm; The particle size of Mo2C powder is 0.1-0.3 μm. Transition area composition includes WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) is: 79wt%, 14wt%, 4.6wt%, 2wt%, 0.4wt%, NbC is set on the side of the transition area close to the drill tip area, the thickness is 60 μm; Among them, the powder particle size of WC, Co, ZrC is 0.5-1.0 μm; The particle size of the particles is 50-80 nm; the particle size of the NbC powder is 50-100 nm; and the length of the carbon nanotube is 5-10 μm. The shank region composition comprises WC, Co, Ni and ZrC, and the content of each component (i.e. WC, Co, Ni and ZrC) is 69 wt%, 24 wt%, 4 wt% and 3 wt% respectively; wherein the powder particle size of WC, Co, Ni and ZrC is 2-5 μm.

[0043] A preparation method of a multi-region gradient cemented carbide material, comprising: Step S1, drill tip region preparation: first, the components of the drill tip region are proportioned, and SiC-B4C composite particles and TaC powder are pretreated; specifically: the surface of the ball-milled SiC-B4C composite particles (i.e. SiC particles and B4C particles are mixed and ball-milled at a mass ratio of 1:1 to obtain SiC-B4C composite particles with a particle size of 0.1-0.3 μm) is modified with a silane coupling agent (KH550), and the silane coupling agent accounts for 1.2 wt% of the SiC-B4C composite particles (enhancing wettability); the TaC powder is vacuum dried at a temperature of 130°C for 1.5 h (to remove adsorbed water and avoid the formation of pores during the sintering process).

[0044] Then, in a high-energy planetary mill under the protection of an inert gas (such as argon), the ball-to-powder ratio is 10:1, the grinding balls are WC-Co alloy balls with a diameter of 5 mm, the dispersion medium is anhydrous ethanol (solid-liquid ratio 1:1.2) and oleic acid (amount 0.3 wt%), TiCN, ZrC and Mo2C are first ball-milled, the ball-milling speed is 320 rpm and the time is 0.8 h; then AlTiN and SiC-B4C composite particles are added and ball-milled after ultrasonic dispersion, the ultrasonic dispersion frequency is 22 kHz and the time is 28 min, the ball-milling speed is 420 rpm and the time is 1.8 h; the ball-milled slurry is vacuum dried (vacuum drying temperature 120°C, time 1.5 h) to obtain the drill tip region preliminary powder.

[0045] Step S2, transition region preparation: first, the (W, Zr)C solid solution powder is prepared in proportion, specifically: tungsten powder, zirconium powder and graphite powder are weighed according to the mass ratio of WC and ZrC in the transition region, rare earth element oxide is added, the rare earth element is Eu, then the raw materials and tungsten carbide balls are loaded into a stainless steel vacuum ball mill pot for high-energy ball milling (ball-to-powder ratio 8:1), the ball-milling speed is 520 rpm and the time is 7.5 h; then the ball-milled product is placed in a high-temperature atmosphere furnace and subjected to a thermal combination reaction in a nitrogen-hydrogen mixed gas atmosphere (volume ratio of nitrogen to hydrogen 5:2) at a temperature of 900°C for 1.5 h to obtain the (W, Zr)C solid solution powder.

[0046] Then part of the (W, Zr) C solid solution powder (the amount of W element in the (W, Zr) C solid solution powder here is the same as The W content in the nanoparticles is consistent with that in the Co powder. The precursor was obtained by mixing the precursor with an atomic ratio of Co:W (i.e., Co:W=1:1), adding nano-tungsten powder (particle size of about 50nm, the atomic ratio of nano-tungsten powder to cobalt powder is 1:1, used to supplement tungsten) and carbon nanotubes, and ball milling was carried out in an argon atmosphere at a ball milling speed of 320rpm for 3.5h to obtain the precursor; the precursor was placed in a tube furnace, hydrogen was introduced into the tube furnace (hydrogen flow rate 6L / min), and heated to generate carbon nanotubes adsorbed on the surface. Nanoparticles, heating temperature is 870℃, and holding time is 1.8h.

[0047] Then, Co powder and the remaining (W, Zr)C solid solution powder were added and mixed by ball milling in an argon atmosphere at a ball milling speed of 320 rpm for 2 hours. The mixed powder was vacuum dried (vacuum drying temperature of 120°C for 1.5 hours) and reduced again by hydrogen in a tube furnace (hydrogen flow rate of 8 L / min, holding time of 800°C for 1.5 hours). After reduction, it was vacuum ball milled (ball milling speed of 320 rpm for 2 hours) and spray dried (conventional spray drying method can be used) to obtain a transition zone preparatory powder. Step S3, Preparation of the Drill Shank: Using a gas atomization method, Co powder and Ni powder are melted in a proportional manner to obtain a Co-Ni pre-alloyed powder. Specifically, the Co and Ni powders are melted in a proportional manner at 1650°C, then atomized using argon gas at a pressure of 0.55 MPa to produce a pre-alloyed powder with a particle size of 2-5 μm. Simultaneously, a (W, Zr)C solid solution powder is prepared according to the mass ratio of WC to ZrC in the drill shank region (preparation method step S2).

[0048] The (W, Zr) C solid solution powder and Co-Ni pre-alloyed powder prepared by mixing in proportion are added with ethanol as the medium, and a grain inhibitor is used. The grain inhibitor is VC with a content of 0.3wt%. The mixed powder is ball-milled in an argon atmosphere with a ball-to-material ratio of 8:1, a ball milling speed of 220 rpm, and a ball milling time of 1.8 h. The mixed powder is vacuum dried (vacuum drying temperature is 120°C, time is 1.5 h), and reduced in a tube furnace with hydrogen (hydrogen flow rate is 8 L / min, holding time is 800°C, holding time is 1.5 h). After reduction, it is vacuum ball milled (ball milling speed is 220 rpm, time is 1.8 h), and spray dried (conventional spray drying method can be used) to obtain the drill shank area preparation powder.

[0049] Step S4, material forming: the drill shank area, transition area, drill tip area in order to prepare the powder, transition area, drill tip area of the prepared powder layering pressing, layering pressing process, transition area away from the drill shank area on the side surface in turn laying NbC layer and TaC layer (i.e. first pressing drill shank area, then pressing transition, then laying NbC layer and TaC layer in turn, finally pressing drill tip area); layering pressing using cold isostatic pressing pre-pressing, pressing pressure is 300 MPa, time is 8 min.

[0050] Finally in nitrogen atmosphere, gradient hot isostatic pressing diffusion, specifically: first at 1120℃, 110 MPa, 0.9 h; then at 1370℃, 135 MPa, 1.9 h; finally at 1420℃, 160 MPa, 1.9 h; obtain cemented carbide material.

[0051] Comparative example 1: A kind of cemented carbide material, from outer layer (i.e. drill bit front end) to inner layer (i.e. rear end) includes drill tip area, transition area and drill shank area, drill tip area thickness is 0.6 μm, transition area thickness is 0.6 μm, drill shank area thickness is 2.0 μm. Drill tip area composition includes AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C, the content of each component (i.e. AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) is: 4wt%, 90wt%, 1.5wt%, 3wt%, 0.5wt%, TaC is set in drill tip area near transition area on one side, thickness is 50 μm;Among them, the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2 μm;The particle size of SiC-B4C composite particles is 0.1-0.3 μm, the mass ratio of SiC and B4C in composite particles is 1:1;The particle size of TaC powder is 50-100 nm;The particle size of Mo2C powder is 0.1-0.3 μm. Transition area composition includes WC, Co, ZrC, nanoparticles and carbon nanotubes, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) is: 77wt%, 16wt%, 4wt%, 2.5wt%, 0.5wt%;Among them, the powder particle size of WC, Co, ZrC is 0.5-1.0 μm; The particle size of the particles is 50-80 nm; the length of the carbon nanotube is 5-10 μm. Drill shank area composition includes WC, Co, Ni and ZrC, the content of each component (i.e. WC, Co, Ni and ZrC) is: 67wt%, 26wt%, 3.5wt%, 3.5wt%;Among them, the powder particle size of WC, Co, Ni, ZrC is 2-5 μm.

[0052] Comparative example 2: A hard alloy material, from the outer layer (i.e. the front end of the drill bit) to the inner layer (i.e. the rear end) includes a drill tip area, a transition area and a drill handle area, the drill tip area thickness is 0.6μm, the transition area thickness is 0.6μm, the drill handle area thickness is 2.0μm. The composition of the drill tip area includes AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C, the content of each component (i.e. AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) is: 4wt%, 90wt%, 1.5wt%, 3wt%, 0.5wt% respectively; wherein, the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2μm; the particle size of SiC-B4C composite particles is 0.1-0.3μm, the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of Mo2C powder is 0.1-0.3μm. The composition of the transition area includes WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) is: 77wt%, 16wt%, 4wt%, 2.5wt%, 0.5wt% respectively; NbC is arranged on the side of the transition area close to the drill tip area, with a thickness of 50μm; wherein, the powder particle size of WC, Co, ZrC is 0.5-1.0μm; the particle size of the particles is 50-80nm; the particle size of NbC powder is 50-100nm; the length of the carbon nanotube is 5-10μm. The composition of the drill handle area includes WC, Co, Ni and ZrC, the content of each component (i.e. WC, Co, Ni and ZrC) is: 67wt%, 26wt%, 3.5wt%, 3.5wt% respectively; wherein, the powder particle size of WC, Co, Ni, ZrC is 2-5μm.

[0053] Comparative Example 3: A hard alloy material, from the outer layer (i.e. the front end of the drill bit) to the inner layer (i.e. the rear end) includes a drill tip area, a transition area and a drill handle area, the drill tip area thickness is 0.6μm, the transition area thickness is 0.6μm, the drill handle area thickness is 2.0μm. The composition of the drill tip area includes AlTiN, TiCN, ZrC, B4C particles, TaC and Mo2C, the content of each component (i.e. AlTiN, TiCN, ZrC, B4C particles and Mo2C) is: 4wt%, 90wt%, 1.5wt%, 3wt%, 0.5wt% respectively, TaC is arranged on the side of the drill tip area close to the transition area, with a thickness of 50μm; wherein, the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2μm; the particle size of B4C particles is 0.1-0.3μm; the particle size of TaC powder is 50-100nm; the particle size of Mo2C powder is 0.1-0.3μm. The composition of the transition area includes WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) is 77wt%, 16wt%, 4wt%, 2.5wt%, 0.5wt% in turn, NbC is arranged on the side of the transition zone close to the drill tip zone with a thickness of 50μm; wherein the powder particle size of WC, Co, ZrC is 0.5-1.0μm; The particle size of the particles is 50-80nm; the particle size of the NbC powder is 50-100nm; the length of the carbon nanotubes is 5-10μm. The composition of the shank zone includes WC, Co, Ni and ZrC, the content of each component (i.e. WC, Co, Ni and ZrC) is 67wt%, 26wt%, 3.5wt%, 3.5wt% in turn; wherein the powder particle size of WC, Co, Ni, ZrC is 2-5μm.

[0054] Comparative Example 4: A cemented carbide material includes a drill tip zone, a transition zone and a shank zone from the outer layer (i.e. the front end of the drill) to the inner layer (i.e. the rear end), the thickness of the drill tip zone is 0.6μm, the thickness of the transition zone is 0.6μm, and the thickness of the shank zone is 2.0μm. The composition of the drill tip zone includes AlTiN, TiCN, ZrC, SiC-B4C composite particles and TaC, the content of each component (i.e. AlTiN, TiCN, ZrC and SiC-B4C composite particles) is 4wt%, 90wt%, 1.5wt%, 3.5wt% in turn, TaC is arranged on the side of the drill tip zone close to the transition zone with a thickness of 50μm; wherein the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2μm; the particle size of SiC-B4C composite particles is 0.1-0.3μm, the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of TaC powder is 50-100nm. The composition of the transition zone includes WC, Co, ZrC, nanoparticles, NbC and carbon nanotubes, the content of each component (i.e. WC, Co, ZrC, nanoparticles and carbon nanotubes) is 77wt%, 16wt%, 4wt%, 2.5wt%, 0.5wt% in turn, NbC is arranged on the side of the transition zone close to the drill tip zone with a thickness of 50μm; wherein the powder particle size of WC, Co, ZrC is 0.5-1.0μm; The particle size of the particles is 50-80nm; the particle size of the NbC powder is 50-100nm; the length of the carbon nanotubes is 5-10μm. The composition of the shank zone includes WC, Co, Ni and ZrC, the content of each component (i.e. WC, Co, Ni and ZrC) is 67wt%, 26wt%, 3.5wt%, 3.5wt% in turn; wherein the powder particle size of WC, Co, Ni, ZrC is 2-5μm.

[0055] Comparative Example 5: A cemented carbide material, including a drill tip area, a transition area and a drill shank area from the outer layer (i.e., the front end of the drill bit) to the inner layer (i.e., the rear end). The thickness of the drill tip area is 0.6μm, the thickness of the transition area is 0.6μm, and the thickness of the drill shank area is 2.0μm. The components of the drill tip area include AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C. The contents of each component (i.e., AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) are: 4wt%, 90wt%, 1.5wt%, 3wt% and 0.5wt% respectively. TaC is arranged on one side of the drill tip area close to the transition zone with a thickness of 50μm. Among them, the powder particle size of AlTiN, TiCN and ZrC is 0.1-0.2μm; the particle size of SiC-B4C composite particles is 0.1-0.3μm, and the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of TaC powder is 50-100nm; and the particle size of Mo2C powder is 0.1-0.3μm. The transition zone consists of WC, Co, ZrC, NbC, and carbon nanotubes (CNTs). The content of each component (WC, Co, ZrC, and CNTs) is 77wt%, 16wt%, 4wt%, and 3wt%, respectively. NbC is deposited on the side of the transition zone near the drill tip, with a thickness of 50μm. The WC, Co, and ZrC powders have a particle size of 0.5-1.0μm, the NbC powder has a particle size of 50-100nm, and the CNTs have a length of 5-10μm. The shank zone consists of WC, Co, Ni, and ZrC. The content of each component (WC, Co, Ni, and ZrC) is 67wt%, 26wt%, 3.5wt%, and 3.5wt%, respectively. The WC, Co, Ni, and ZrC powders have a particle size of 2-5μm.

[0056] Comparative Example 6: A cemented carbide material, from outer layer (i.e. drill bit front end) to inner layer (i.e. rear end) comprises drill tip area, transition area and drill shank area, the thickness of drill tip area is 0.6μm, the thickness of transition area is 0.6μm, the thickness of drill shank area is 2.0μm. The composition of drill tip area comprises AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C, the content of each component (i.e. AlTiN, TiCN, ZrC, SiC-B4C composite particles and Mo2C) is 4wt%, 90wt%, 1.5wt%, 3wt%, 0.5wt% in turn; TaC is arranged on the side of drill tip area close to transition area, the thickness is 50μm; wherein, the powder particle size of AlTiN, TiCN, ZrC is 0.1-0.2μm; the particle size of SiC-B4C composite particles is 0.1-0.3μm, the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of TaC powder is 50-100nm; the particle size of Mo2C powder is 0.1-0.3μm. The composition of transition area comprises WC, Co, ZrC, nanoparticles and NbC, the content of each component (i.e. WC, Co, ZrC and nanoparticles) is 77wt%, 16wt%, 4wt%, 3wt% in turn; NbC is arranged on the side of transition area close to drill tip area, the thickness is 50μm; wherein, the powder particle size of WC, Co, ZrC is 0.5-1.0μm; the particle size of nanoparticles is 50-80nm; the particle size of NbC powder is 50-100nm. The composition of drill shank area comprises WC, Co, Ni and ZrC, the content of each component (i.e. WC, Co, Ni and ZrC) is 67wt%, 26wt%, 3.5wt%, 3.5wt% in turn; wherein, the powder particle size of WC, Co, Ni, ZrC is 2-5μm.

[0057] The cemented carbide material prepared by example 1 to example 3 and comparative example 1 to comparative example 6 is respectively tested for hardness, bending strength, cyclic wear resistance, fracture toughness and high temperature stability: The hardness, bending strength and fracture toughness can be tested by conventional testing method in the art; Cyclic wear resistance: wet corrosion wear is carried out in 30% quartz sand aqueous solution (pH=3), the impact frequency is 5Hz, the impact energy is 2J, and the cycle is 200h; High temperature stability: thermal shock cycle is carried out at 800℃; The test results are as follows:

[0058] In summary: the hard alloy material prepared by the method has high hardness, large bending strength and high fracture toughness, has excellent wear resistance and high temperature stability, has small internal stress and high bonding strength between layers, can realize near net forming of complex components, and has no cobalt phase enrichment, good dispersity, effectively eliminates brittle phase, and improves overall service reliability.

Claims

1. A multi-region gradient cemented carbide material, characterized by: From the outer layer to the inner layer, it includes the drill tip area, the transition area and the drill shank area. The components of the drill tip area include AlTiN, TiCN, ZrC, SiC-B4C composite particles, TaC and Mo2C. The components of the transition area include WC, Co, ZrC, Nanoparticles, NbC and carbon nanotubes, the drill shank components include WC, Co, Ni and ZrC.

2. The multi-region gradient cemented carbide material according to claim 1, characterized in that: The contents of AlTiN, TiCN, ZrC, SiC-B4C composite particles, and Mo2C in the drill tip area are 3-5wt%, 88-92wt%, 1-2wt%, 2.5-3.5wt%, and 0.3-0.7wt%, respectively. TaC is arranged on one side of the drill tip area close to the transition area and has a thickness of 40-60μm. The powder particle sizes of AlTiN, TiCN, and ZrC are 0.1-0.2μm; the particle size of the SiC-B4C composite particles is 0.1-0.3μm, and the mass ratio of SiC to B4C in the composite particles is 1:1; the particle size of the TaC powder is 50-100nm; and the particle size of the Mo2C powder is 0.1-0.3μm.

3. The multi-region gradient cemented carbide material according to claim 1 or 2, characterized in that: WC, Co, ZrC, The contents of nanoparticles and carbon nanotubes are 75-79wt%, 14-18wt%, 3-5wt%, 2-3wt%, and 0.4-0.6wt%, respectively. NbC is arranged on one side of the transition zone close to the drill tip, with a thickness of 40-60 μm. The particle size of WC, Co, and ZrC powders is 0.5-1.0 μm. The particle size of the particles is 50-80 nm; the particle size of the NbC powder is 50-100 nm; and the length of the carbon nanotubes is 5-10 μm.

4. The multi-region gradient cemented carbide material according to claim 2 or 3, characterized in that: The contents of WC, Co, Ni and ZrC in the drill shank area are 65-69wt%, 24-28wt%, 3-4wt% and 3-4wt% respectively; wherein the powder particle size of WC, Co, Ni and ZrC is 2-5μm.

5. The method for preparing a multi-region gradient cemented carbide material according to claims 1 to 4, characterized in that: include: Step S1, preparation of the drill tip region: First, the components of the drill tip region are proportioned and the SiC-B4C composite particles and TaC powder are pretreated; then, in a high-energy planetary grinder under inert gas protection, using WC-Co alloy balls with a diameter of 5 mm and anhydrous ethanol and oleic acid as the dispersion medium, TiCN, ZrC, and Mo2C are first added and ball-milled, and then AlTiN and SiC-B4C composite particles are added, ultrasonically dispersed, and then ball-milled; the ball-milled slurry is vacuum-dried to obtain a preparatory powder for the drill tip region; Step S2, transition zone preparation: first prepare (W, Zr) C solid solution powder according to the proportion; then mix part of the (W, Zr) C solid solution powder, Co powder and carbon nanotubes to in situ generate adsorbed carbon nanotubes. Nanoparticles; then, Co powder and the remaining (W, Zr)C solid solution powder are added and mixed and ball-milled in an argon atmosphere; the mixed powder is vacuum dried and then reduced again by passing hydrogen in a tube furnace, and then vacuum ball-milled and spray-dried to obtain a transition zone preparatory powder; Step S3, preparation of the drill shank region: using a gas atomization method, Co powder and Ni powder are melted in proportion to obtain Co-Ni pre-alloyed powder; (W, Zr) C solid solution powder and Co-Ni pre-alloyed powder prepared by mixing in proportion are mixed with ethanol as a medium and a grain inhibitor is added, and mixed and ball-milled under an argon atmosphere; the mixed powder is vacuum dried and then reduced in a tube furnace with hydrogen, and then vacuum ball-milled and spray-dried to obtain a preparatory powder for the drill shank region; Step S4, material forming: the prepared powder of the drill shank area, the prepared powder of the transition area, and the prepared powder of the drill tip area are layered and pressed in the order of the drill shank area, the transition area, and the drill tip area. During the layered pressing process, an NbC layer and a TaC layer are sequentially laid on the surface of the transition area away from the drill shank area. Finally, gradient hot isostatic pressing and diffusion are performed in a nitrogen atmosphere to obtain a cemented carbide material.

6. The method for preparing a multi-region gradient cemented carbide material according to claim 5, characterized in that: The specific method of "pre-treating the SiC-B4C composite particles and TaC powder" in step S1 is: using a silane coupling agent to modify the surface of the ball-milled SiC-B4C composite particles, where the silane coupling agent accounts for 0.8 to 1.2 wt% of the SiC-B4C composite particles; and vacuum drying the TaC powder at a temperature of 110 to 130° C. for a drying time of 1.5 to 2.5 hours.

7. The method for preparing a multi-region gradient cemented carbide material according to claim 5, characterized in that: In step S1, TiCN, ZrC, and Mo2C are first added and ball-milled at a speed of 280 to 320 rpm for 0.8 to 1.2 h; then AlTiN and SiC-B4C composite particles are added and ball-milled at a speed of 380 to 420 rpm for 1.8 to 2.2 h, and the frequency of ultrasonic dispersion is 18 to 22 kHz for 28 to 32 min.

8. The method for preparing a multi-region gradient cemented carbide material according to claim 5, characterized in that: In step S4, the layered pressing is performed by cold isostatic pressing for pre-pressing, with a pressing pressure of 250 to 300 MPa and a pressing time of 8 to 12 minutes.

9. The method for preparing a multi-region gradient cemented carbide material according to claim 5, characterized in that: The gradient hot isostatic pressing diffusion in step S4 is specifically as follows: first, keep warm at 1080-1120° C. and 90-110 MPa for 0.9-1.1 h; then keep warm at 1330-1370° C. and 115-135 MPa for 1.9-2.1 h; and finally, keep warm at 1380-1420° C. and 140-160 MPa for 1.9-2.1 h.

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