A co-high-entropy carbide cermet material, a preparation method and application thereof

Abstract

The application discloses a kind of co-high-entropy carbide cermet materials and preparation method and application thereof, belong to the field of cermet material.The co-high-entropy carbide cermet material provided by the application is with (WVMoTaTi) C ceramic as matrix, directly adding its corresponding metal elements (W element, V element, Mo element, Ta element, Ti element) as binder phase by discharge plasma coupling high-frequency induction sintering.The preparation method is to mix all raw materials in proportion first, then ball mill, dry to obtain mixed powder, and discharge plasma coupling high-frequency induction sintering is used.The application provides a kind of co-high-entropy carbide cermet material with high-entropy carbide solid solution and high-entropy alloy coexisting, which has excellent comprehensive mechanical properties, high precision and high-speed cutting ability, and shows irreplaceable importance in tool material, precision machining and other fields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of cermet materials, and particularly relates to a co-high-entropy carbide cermet material, a preparation method and application thereof. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing the understanding of the general background of the application and does not necessarily constitute an admission or a recognition that the information forms part of the prior art that is already known in any country in the world.

[0003] High-entropy ceramic material is a new type of ceramic material composed of five or more components in equimolar or near-equimolar proportions. It draws on the design concept of high-entropy alloy, uses significant high-configuration entropy to stabilize the crystal structure, realizes high-disorder of composition and structure through entropy driving, and then forms a single solid solution phase, which makes high-entropy ceramic material obtain comprehensive performance that traditional ceramic material cannot achieve, such as higher hardness. However, high-entropy ceramic material also has some defects, such as the inherent brittleness of ceramic material, which leads to low strength and poor toughness. In addition, high-entropy formation difficulty is also a big problem of high-entropy ceramic material. The formation of high-entropy ceramic is a high-temperature stable process dominated by entropy. However, this entropy stabilization usually needs to overcome the enthalpy change of forming multiple simple compounds (which are more stable in thermodynamics) at very high temperatures. If the sintering temperature or holding time is not properly controlled, it is easy to appear mixed phase or phase separation. In addition, lattice distortion makes it difficult for elements to achieve uniform mixing at the atomic level through sufficient diffusion during the sintering process of high-entropy ceramic, which is also one of the reasons for high-entropy formation difficulty.

[0004] The addition of metal binder phase can significantly improve the performance of high-entropy ceramic material, especially in toughness and strength. Metal binder phase hinders crack propagation through crack deflection, bridging, branching, and phase transformation toughening, etc. to improve toughness. In addition, the plastic deformation of metal can absorb energy and inhibit the abnormal growth of hard phase grains, which makes high-entropy ceramic material maintain high hardness, while improving the bending strength and promoting the solid solution of ceramic phase. However, the mismatch of thermal expansion coefficient between metal binder phase and ceramic phase will lead to different degrees of shrinkage during sintering and cooling. This uneven shrinkage will generate huge residual thermal stress in the material, which will "expel" the metal binder phase to the lower energy three-pronged grain boundary and enrich here. In addition, high-entropy ceramic phase itself has serious lattice distortion and sluggish diffusion effect, which makes it extremely difficult for atoms in the metal binder phase to diffuse into the interior of the ceramic lattice, resulting in insufficient solid solution caused by heterogeneous crystal diffusion.

[0005] The prior art discloses that the introduction of metal Cr in the (TiZrNbTaCr)C high-entropy carbide ceramic prepared by a hot-pressing sintering method can improve the high-temperature bending strength of the material, but with the increase of the sintering temperature, the addition of the Cr element introduces low-melting-point chromium carbide, which is segregated at the grain boundaries and is not conducive to the improvement of the strength at high temperatures. The fracture mode at high temperatures is mainly intergranular fracture, and the bending strength decreases with the increase of the temperature.

[0006] Therefore, how to provide a high-entropy metal ceramic material with higher strength, toughness, and still retaining higher hardness to adapt to the high-precision and high-speed cutting field is an urgent problem to be solved. SUMMARY

[0007] In order to solve the problems of the prior art, the purpose of the present application is to provide a co-high-entropy carbide metal ceramic material and a preparation method and application thereof. The co-high-entropy carbide metal ceramic material provided by the present application is a (WVMoTaTi)C ceramic as a substrate, directly adding corresponding metal elements (W element, V element, Mo element, Ta element, Ti element) as a binder phase to form by discharge plasma coupling high-frequency induction sintering. The preparation method is to mix WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder in proportion, then ball mill and dry to obtain a mixed powder, and then adopt discharge plasma coupling high-frequency induction sintering. Because the metal ceramic material has a high metal concentration, the solid solution effect is promoted, and more metal binder phases can be ensured to be located at the grain boundaries and form a high-entropy alloy, so that it has higher strength and toughness, and still retains higher hardness. With its excellent comprehensive mechanical properties, high-precision and high-speed cutting ability, it has shown irreplaceable importance in the fields of tool materials and precision machining.

[0008] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0009] In a first aspect, the present application provides a co-high-entropy carbide metal ceramic material, which comprises a substrate and a metal binder phase, and the substrate is a high-entropy carbide and the metal binder phase is a high-entropy alloy, and the co-high-entropy carbide metal ceramic material is a high-entropy carbide solid solution coexisting with a high-entropy alloy.

[0010] The substrate is a high-entropy carbide (WVMoTaTi)C; the metal elements in the high-entropy carbide and the high-entropy alloy are the same; the molar ratio of each carbide in the high-entropy carbide is the same; and the molar ratio of each metal element in the high-entropy alloy is the same.

[0011] The volume ratio of the matrix and the binder phase is 100%. The volume ratio of the matrix is 80-95%, and specifically can be 80%, 85%, 88%, 90%, 92%, 95%, etc., and the volume ratio of the metal binder phase is 5-20%, and specifically can be 5%, 8%, 10%, 12%, 15%, 20%, etc. If the ratio between the matrix and the binder phase is too high or too low, the bending strength, fracture toughness and Vickers hardness of the ceramic material will be affected. In order to obtain better mechanical properties, the volume ratio of the matrix is preferably 88-92%, and most preferably 90%, and the volume ratio of the metal binder phase is preferably 8-12%, and most preferably 10%.

[0012] The application provides a co-high-entropy method for forming high-entropy carbide solid solution and high-entropy alloy with the same component synchronously. On the one hand, the high-entropy alloy is formed earlier than the high-entropy carbide solid solution, that is, before the formation of the high-entropy carbide solid solution, each metal atom is highly uniformly mixed and distributed around the high-entropy carbide solid solution to be formed, so that a single-phase and non-segregated high-entropy carbide is easily obtained. On the other hand, the consistent cations provide interface compatibility and bonding strength, inhibit thermal expansion adaptation, and enhance the stability of the high-entropy system.

[0013] The application adopts V element, the mixing enthalpy of V element and other main elements W element, Mo element, Ta element and Ti element is close to zero, and the chemical interaction is weak. The formation of high-entropy alloy is earlier than that of high-entropy solid solution, which is more conducive to the formation of disordered solid solution and the inhibition of sigma phase precipitation, which can significantly improve the strength of the material system and form a high-strength high-entropy metal ceramic material. At the same time, there is no need to add other phases to improve the solid solution, which reduces the possibility of producing impurity phases. For example, if Nb element is used, in the W-Nb-Mo-Ta-Ti high-entropy alloy system formed first, the W element, Mo element and Ta element also tend to form sigma phase, and the addition of Nb element further increases the average atomic size difference and mixing enthalpy, aggravates local ordering, and increases the nucleation driving force of sigma phase when the high-entropy carbide solid solution is formed, resulting in the hard and brittle characteristics of the material. That is, if Nb element is introduced, the high-temperature phase stability can be enhanced and the grain coarsening at high temperature can be inhibited, but the disadvantage is that the content of Nb element is high, and the solid solubility in the high-entropy material system is poor, and a topologically close-packed phase sigma phase with high hardness and high brittleness is locally generated, forming a Nb-rich region, which will become a crack source and cause low material strength, which will affect the performance of the final material. Therefore, in order to obtain a metal ceramic material with higher strength, higher toughness and higher hardness, Nb element cannot be added.

[0014] In one or more embodiments, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1. In the present application, each carbide in the ceramic matrix is in an equimolar ratio, and each metal element in the added metal is also in an equimolar ratio, which is to ensure the formation of high-entropy carbide ceramics and high-entropy alloys.

[0015] The "high-entropy carbide solid solution" belongs to high-entropy carbide ceramics. The same metal elements are selected to increase the concentration of metal elements, and the same proportion is to form high entropy. The combination of the two forms a high-entropy carbide metal ceramic material.

[0016] In a second aspect, the present application provides a preparation method of the above-mentioned high-entropy carbide metal ceramic material, comprising the following steps:

[0017] S1, mixing WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder in a set ratio to obtain a raw material mixture, and placing the raw material mixture in a polyethylene glycol-anhydrous ethanol dispersion solution to prepare a mixed solution;

[0018] S2, ball milling, drying, and sieving the mixed solution to obtain a mixed powder;

[0019] S3, performing spark plasma sintering on the mixed powder, and obtaining the high-entropy carbide metal ceramic material.

[0020] In one or more embodiments, in step S1, polyethylene glycol is added to anhydrous ethanol, and stirred in a water bath constant temperature, and cooled to room temperature to prepare a polyethylene glycol-anhydrous ethanol dispersion solution.

[0021] The molecular weight of the polyethylene glycol is 6000, that is, PEG 6000.

[0022] The dispersion amount of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion solution is 2-4 g / L.

[0023] The temperature of the water bath constant temperature is 55-65℃, the stirring is magnetic stirring, and the stirring time is 10-15 min.

[0024] In one or more embodiments, in step S1, the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion solution is 0.09%-1.1% of the mass sum of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder.

[0025] In one or more embodiments, in step S1, the mixed solution is prepared by ultrasonic dispersion and stirring; the ultrasonic dispersion time is 55-60 min, and the stirring is mechanical stirring.

[0026] In one or more embodiments, in step S1, the average particle size of the WC powder, the VC powder, the Mo2C powder, the TaC powder, the TiC powder, the W powder, the V powder, and the Ta powder is 1-3 μm. The average particle size of the Mo powder and the Ti powder is 0.8-1.2 μm, preferably 1 μm.

[0027] In one or more embodiments, in step S2, the ball milling step is as follows: the mixed solution and the grinding balls are poured into a jar, the total mass of the raw material mixture and the weight of the grinding balls are in a ratio of 1:(8-20), preferably 1:(8-12), and most preferably 1:10, and the ball milling is performed under a protective atmosphere for 45-50 h.

[0028] The protective atmosphere for the ball milling is nitrogen, and the grinding balls used in the ball milling are cemented carbide grinding balls. The cemented carbide balls are mixed cemented carbide grinding balls with a diameter of 5 mm and a diameter of 10 mm, and the mass ratio of the cemented carbide balls with a diameter of 5 mm to the cemented carbide balls with a diameter of 10 mm is (1-2):(1-5). The ball milling is a high-energy ball milling process, and a planetary high-energy ball mill is used. The ball milling is performed under nitrogen protection and water cooling at a rotation speed of 300-500 rpm, preferably 400 rpm.

[0029] In one or more embodiments, in step S2, the drying includes vacuum drying, the vacuum drying temperature is 100-120℃, the vacuum drying time is 24-48 h, preferably 36 h, and the screen mesh for sieving is 100-200 meshes, preferably 100 meshes.

[0030] In one or more embodiments, in step S3, the mixed powder is placed in a graphite mold, and discharge plasma coupled high-frequency induction sintering is performed under a vacuum atmosphere.

[0031] The discharge plasma coupled high-frequency induction sintering conditions are as follows: the sintering temperature is 1350-1500℃ (specifically, 1350℃, 1400℃, 1420℃, 1430℃, 1440℃, 1450℃, 1460℃, 1470℃, 1480℃, 1500℃, etc., preferably 1430-1470℃, and most preferably 1450℃), the sintering pressure is 30-40 MPa, the heating rate is preheating to 565-575℃ (preferably 570℃) and heating to 595-605℃ (preferably 600℃) within 1 min, heating to 895-905℃ (preferably 900℃) at a rate of 95-105℃ / min (preferably 100℃ / min), heating to 1245-1255℃ (preferably 1250℃) at a rate of 70-80℃ / min (75℃ / min), and heating to the target temperature at a rate of 45-55℃ / min (50℃ / min), and the holding time is 8-12 min (preferably 10 min).

[0032] As a preferred embodiment, the preparation method of the co-high-entropy carbide cermets material comprises the following steps:

[0033] (1) Polyethylene glycol is added into anhydrous ethanol, and stirred in a water bath constant temperature, and cooled to room temperature to prepare a polyethylene glycol-anhydrous ethanol dispersion solution;

[0034] (2) WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, Ti powder are mixed, and added into the prepared polyethylene glycol-anhydrous ethanol dispersion solution, ultrasonic dispersion and stirring to prepare a required mixed solution;

[0035] (3) The prepared mixed solution is ball milled under a protective atmosphere;

[0036] (4) The ball milled slurry is vacuum dried and sieved to prepare a mixed powder;

[0037] (5) The mixed powder is placed in a graphite mold, and discharge plasma coupling high-frequency induction sintering is carried out under a vacuum atmosphere to prepare the co-high-entropy carbide cermets material.

[0038] In a third aspect, the present application provides an application of the above-mentioned co-high-entropy carbide cermets material in the field of high-precision machining, high-speed or ultra-high-speed cutting, etc. Such as an application in the preparation of high-precision machining tools, high-speed or ultra-high-speed cutting tools.

[0039] One or some of the above technical solutions have the following advantages or beneficial effects:

[0040] (1) The co-high-entropy carbide cermets material provided by the present application has the same metal elements and proportions in the high-entropy carbide and the high-entropy alloy. That is, the present application is a co-high-entropy design with the same metal carbide and metal elements as the matrix and the binder phase respectively, which increases the metal concentration in the material system, increases the driving force for substitutional solid solution, and promotes the formation of high-entropy carbide solid solution. Secondly, the high-entropy carbide solid solution is formed in a high-concentration metal element environment, which objectively keeps the metal binder phase at the grain boundary, overcoming the defect that the metal binder phase in traditional metal ceramics is mostly located at the three-pronged grain boundary, and improving the grain boundary bonding strength. Finally, the metal binder phase left at the grain boundary undergoes solid solution under the action of compressive stress, forming a high-entropy alloy, that is, a co-high-entropy carbide cermets material coexisting with a high-entropy carbide solid solution and a high-entropy alloy, overcoming the problems of low strength and poor toughness of (WVMoTaTi)C ceramic materials, and significantly improving the comprehensive mechanical properties. Compared with existing ceramic tool materials, the metal ceramic material has higher toughness and hardness, and can be applied to high-precision machining and ultra-high-speed cutting fields.

[0041] (2) The co-high-entropy carbide cermet material of the present application, W powder, V powder, Mo powder, Ta powder, Ti powder and WC powder, VC powder, Mo2C powder, TaC powder, TiC powder are mixed, ball milled, vacuum dried to obtain a sintering precursor of the cermet material, and the process of separately preparing high-entropy alloy powder is omitted.

[0042] (3) In the preparation method of the co-high-entropy carbide cermet material of the present application, the mixed powder is obtained by ultrasonic dispersion, high-energy ball milling and constant temperature drying in the early stage, and then discharge plasma coupled high-frequency induction sintering is carried out to obtain a cermet material with high bending strength and high fracture toughness at a sintering temperature of 1450 DEG C.

[0043] (4) The co-high-entropy carbide cermet material provided by the present application is sintered by discharge plasma coupled high-frequency induction sintering technology using WC powder, VC powder, Mo2C powder, TaC powder, TiC powder and the corresponding W powder, V powder, Mo powder, Ta powder, Ti powder as raw materials. The mechanical property parameters of the obtained ceramic material sample after cutting processing are: bending strength 765~822 MPa, fracture toughness 6.93~7.45 MPa·m 1 / 2 , hardness 17.55~18.12 GPa. The obtained co-high-entropy carbide cermet material has excellent comprehensive mechanical properties, and has irreplaceable importance in the fields of cutting tool materials and precision machining, and is expected to be expanded to more fields. BRIEF DESCRIPTION OF DRAWINGS

[0044] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and the schematic embodiments of the present application and the description thereof serve to explain the present application, and do not constitute an improper limitation on the present application.

[0045] Figure 1 The fracture electron microscope graph of the co-high-entropy cermet material prepared for the present application embodiment 3;

[0046] Figure 2 The XRD graph of the co-high-entropy cermet material prepared for the present application embodiment 3. DETAILED DESCRIPTION

[0047] In the present application, unless otherwise specified, other test materials and instruments and equipment are conventional test materials in the art, and can be purchased through commercial channels.

[0048] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below with specific embodiments.

[0049] Embodiment 1

[0050] The average particle size of the WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, and Ta powder in the embodiment is 1-3 μm, the average particle size of the Mo powder and Ti powder is 1 μm, and all are commercially available products. The polyethylene glycol is PEG6000.

[0051] The volume ratio of the ceramic matrix in the co-high-entropy carbide cermets is 90%, the volume ratio of the metal binder phase is 10%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1.

[0052] The preparation method of the co-high-entropy carbide cermets comprises the following steps:

[0053] (1) Take anhydrous ethanol in a beaker, weigh and add polyethylene glycol, place the beaker in a water bath, and magnetically stir at 55°C for 10 min until the polyethylene glycol is completely dissolved, and then cool to room temperature to prepare a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2 g / L;

[0054] (2) Mix the powders according to the volume ratio of the ceramic matrix being 90% and the volume ratio of the metal binder phase being 10%, the molar ratio of each carbide in the matrix being 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase being 1:1:1:1:1, add the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonically disperse for 60 min and mechanically stir to prepare a mixed solution; the mass of the polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the mass of the WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder;

[0055] (3) Place the prepared mixed solution in a ball mill jar, use hard alloy grinding balls for milling, the hard alloy balls are a mixture of hard alloy balls with a diameter of 5 mm and hard alloy balls with a diameter of 10 mm, the mass ratio of the hard alloy balls with a diameter of 5 mm to the hard alloy balls with a diameter of 10 mm is 2:3, and the ball-to-material mass ratio is 10:1, and high-energy ball mill for 48 h under a nitrogen protective atmosphere;

[0056] (4) Vacuum constant temperature dry the ball milled slurry at 120°C for 48 h, pass through a 200 mesh sieve, and prepare a co-high-entropy carbide cermets mixed powder;

[0057] (5) Put the mixed powder of co-high-entropy carbide cermet into a graphite mold, and perform discharge plasma coupling high-frequency induction sintering under a vacuum atmosphere, with a sintering temperature of 1350℃, a sintering pressure of 30 MPa, a temperature rising speed of: preheating to 570℃, and rising to 600℃ within 1 min; rising to 900℃ at a speed of 100℃ / min; rising to 1250℃ at a speed of 75℃ / min; rising to the target temperature at a speed of 50℃ / min, and maintaining for 10 min, to obtain the co-high-entropy carbide cermet material. The obtained ceramic material sample is cut and processed, and the mechanical performance parameters thereof are measured as: a bending strength of 765 MPa, a fracture toughness of 6.93 MPa·m 1 / 2 , and a Vickers hardness of 17.55 GPa.

[0058] Example 2

[0059] Different from Example 1, the sintering temperature in step (5) is 1400℃. The specific steps are as follows:

[0060] The volume ratio of the ceramic matrix in the co-high-entropy carbide cermet material is 90%, the volume ratio of the metal binder phase is 10%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1.

[0061] The preparation method of the co-high-entropy carbide cermet material comprises the following steps:

[0062] (1) Put anhydrous ethanol into a beaker, weigh and add polyethylene glycol, place the beaker in a water bath, and magnetically stir at 55℃ for 10 min until the polyethylene glycol is completely dissolved, and cool to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2g / L;

[0063] (2) Mix the powders according to the volume ratio of the ceramic matrix of 90% and the volume ratio of the metal binder phase of 10%, the molar ratio of each carbide in the matrix of 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase of 1:1:1:1:1, add the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonic dispersion for 60 min and mechanical stirring, to obtain a mixed solution; the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the total mass of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder;

[0064] (3) Put the prepared mixed solution into a ball mill tank, wherein the grinding balls used for the ball milling are cemented carbide grinding balls, the cemented carbide grinding balls are mixed cemented carbide grinding balls with a diameter of 5 mm and a diameter of 10 mm, the mass ratio of the cemented carbide grinding balls with a diameter of 5 mm and 10 mm is 2:3, and the mass ratio of the balls to the material is 10:1, and the ball milling is performed under a nitrogen protective atmosphere for 48 h;

[0065] (4) The ball-milled slurry is dried at 120 DEG C for 48 h under a vacuum constant temperature, sieved through a 200-mesh sieve, and a mixed powder of the co-high-entropy carbide cermet is prepared;

[0066] (5) The mixed powder of the co-high-entropy carbide cermet is placed in a graphite mold, and discharge plasma coupled high-frequency induction sintering is performed under a vacuum atmosphere, the sintering temperature is 1400 DEG C, the sintering pressure is 30 MPa, the heating speed is: preheating to 570 DEG C, and then heating to 600 DEG C within 1 min; heating to 900 DEG C at a speed of 100 DEG C / min; heating to 1250 DEG C at a speed of 75 DEG C / min; heating to the target temperature at a speed of 50 DEG C / min, and the holding time is 10 min, and a co-high-entropy carbide cermet material is prepared. The prepared ceramic material sample is cut and processed, and the mechanical property parameters thereof are measured as follows: the bending strength is 786 MPa, the fracture toughness is 7.08 MPa.m 1 / 2 , and the Vickers hardness is 17.67 GPa.

[0067] Example 3

[0068] Different from example 1, the sintering temperature in step (5) is 1450 DEG C. The specific steps are as follows:

[0069] The volume ratio of the ceramic matrix in the co-high-entropy carbide cermet material is 90%, the volume ratio of the metal binder phase is 10%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1.

[0070] The preparation method of the co-high-entropy carbide cermet material comprises the following steps:

[0071] (1) Put anhydrous ethanol into a beaker, weigh and add polyethylene glycol, put the beaker into a water bath, and magnetically stir at 55 DEG C for 10 min until the polyethylene glycol is completely dissolved, and then cool to room temperature to prepare a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2 g / L;

[0072] (2) The powders were mixed with the following formula: the volume ratio of the ceramic matrix was 90%, the volume ratio of the metal binder phase was 10%, the molar ratio of each carbide in the matrix was 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase was 1:1:1:1:1. The mixture was added to the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonically dispersed for 60 min and mechanically stirred to obtain a mixed solution. The mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion was 0.09% of the sum of the masses of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder.

[0073] (3) The prepared mixed solution is placed in a ball milling jar, wherein the grinding balls used for ball milling are cemented carbide grinding balls, and the cemented carbide grinding balls are a mixture of cemented carbide grinding balls with diameters of 5 mm and 10 mm. The mass ratio of cemented carbide grinding balls with diameters of 5 mm and 10 mm is 2:3, and the mass ratio of ball to material is 10:1. High-energy ball milling is carried out for 48 hours under a nitrogen protective atmosphere.

[0074] (4) The ball mill slurry was dried under vacuum at 120°C for 48 hours and passed through a 200-mesh sieve to obtain a co-high entropy carbide metal-ceramic mixed powder;

[0075] (5) The co-high entropy carbide metal-ceramic mixed powder was placed in a graphite mold and subjected to high-frequency induction sintering via discharge plasma coupling under a vacuum atmosphere. The sintering temperature was 1450℃, the sintering pressure was 30MPa, and the heating rate was as follows: preheating to 570℃ and then heating to 600℃ within 1 min; heating to 900℃ at 100℃ / min; heating to 1250℃ at 75℃ / min; heating to the target temperature at 50℃ / min, and holding for 10 min to obtain the co-high entropy carbide metal-ceramic material. The obtained ceramic material sample was cut and processed, and its mechanical properties were measured as follows: flexural strength 822MPa, fracture toughness 7.45MPa·m. 1 / 2 Vickers hardness 18.12 GPa.

[0076] Figure 1 This is a cross-sectional electron microscope image of the co-high entropy cermet material prepared in Example 3 of the present invention; it can be seen from the image that the high entropy alloys formed by the five metals are mostly located at the grain boundaries and are relatively uniformly dispersed.

[0077] from Figure 2 The XRD patterns show the formation of high-entropy carbide ceramics and high-entropy alloys, respectively. Furthermore, the crystal structures of the high-entropy carbide ceramics and high-entropy alloys are similar, resulting in their peak positions being close and overlapping.

[0078] Example 4

[0079] Different from example 1, the sintering temperature in step (5) is 1500℃. The specific steps are as follows:

[0080] The volume ratio of the ceramic matrix in the co-high-entropy carbide cermets is 90%, the volume ratio of the metal binder phase is 10%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1.

[0081] The preparation method of the co-high-entropy carbide cermets comprises the following steps:

[0082] (1) Take anhydrous ethanol into a beaker, weigh and add polyethylene glycol, place the beaker in a water bath, and magnetically stir at 55℃ for 10 min until the polyethylene glycol is completely dissolved, cool to room temperature, and prepare a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2g / L;

[0083] (2) Mix the powders according to the volume ratio of the ceramic matrix being 90% and the volume ratio of the metal binder phase being 10%, the molar ratio of each carbide in the matrix being 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase being 1:1:1:1:1, add the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonic dispersion for 60 min and mechanical stirring, and prepare a mixed solution; the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the sum of the masses of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder;

[0084] (3) Place the prepared mixed solution in a ball mill jar, use hard alloy grinding balls for milling, the hard alloy balls are a mixture of hard alloy balls with a diameter of 5mm and a diameter of 10mm, the mass ratio of hard alloy balls with a diameter of 5mm and 10mm is 2:3, the ball-to-material mass ratio is 10:1, and high-energy ball milling is carried out under a nitrogen protective atmosphere for 48h;

[0085] (4) Vacuum constant temperature drying of the ball milled slurry at 120℃ for 48h, sieving through a 200 mesh sieve, and preparing a co-high-entropy carbide cermets mixed powder;

[0086] (5) Put the mixed powder of co-high-entropy carbide cermet into a graphite mold, and perform discharge plasma coupling high-frequency induction sintering under a vacuum atmosphere, with a sintering temperature of 1500℃, a sintering pressure of 30 MPa, a temperature rising speed of preheating to 570℃, and rising to 600℃ within 1 min, rising to 900℃ at a speed of 100℃ / min, rising to 1250℃ at a speed of 75℃ / min, and rising to the target temperature at a speed of 50℃ / min, and a holding time of 10 min, to obtain the co-high-entropy carbide cermet material. The obtained ceramic material sample is cut and processed, and the mechanical performance parameters thereof are measured as follows: a bending strength of 803 MPa, a fracture toughness of 7.21 MPa·m 1 / 2 , and a Vickers hardness of 17.86 GPa.

[0087] Example 5

[0088] Different from Example 3, the proportions of the ceramic matrix and the metal binder phase in step (2) are different. The specific steps are as follows:

[0089] The volume ratio of the ceramic matrix in the co-high-entropy carbide cermet material is 95%, the volume ratio of the metal binder phase is 5%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1.

[0090] The preparation method of the co-high-entropy carbide cermet material comprises the following steps:

[0091] (1) Put anhydrous ethanol into a beaker, weigh and add polyethylene glycol, place the beaker in a water bath, and magnetically stir at 55℃ for 10 min until the polyethylene glycol is completely dissolved, and then cool to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2 g / L;

[0092] (2) Mix the powders according to the volume ratio of the ceramic matrix of 95% and the volume ratio of the metal binder phase of 5%, the molar ratio of each carbide in the matrix of 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase of 1:1:1:1:1, add the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonic disperse for 60 min and mechanically stir, to obtain a mixed solution; the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the sum of the masses of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder;

[0093] (3) Put the prepared mixed solution into a ball mill tank, wherein the grinding balls used for the ball milling are cemented carbide grinding balls, the cemented carbide grinding balls are mixed cemented carbide grinding balls with a diameter of 5 mm and a diameter of 10 mm, the mass ratio of the cemented carbide grinding balls with a diameter of 5 mm and 10 mm is 2:3, and the mass ratio of the balls to the material is 10:1, and the ball milling is performed under a nitrogen protective atmosphere for 48 h;

[0094] (4) The ball-milled slurry is dried at 120°C for 48 h under a vacuum constant temperature, sieved through a 200-mesh sieve, and a co-high-entropy carbide cermet mixed powder is prepared;

[0095] (5) The co-high-entropy carbide cermet mixed powder is placed in a graphite mold, and discharge plasma coupled high-frequency induction sintering is performed under a vacuum atmosphere, the sintering temperature is 1450°C, the sintering pressure is 30 MPa, the heating speed is: preheating to 570°C, and then heating to 600°C within 1 min; heating to 900°C at a speed of 100°C / min; heating to 1250°C at a speed of 75°C / min; heating to the target temperature at a speed of 50°C / min, and the holding time is 10 min, and a co-high-entropy carbide cermet material is prepared. The prepared ceramic material sample is cut and processed, and the mechanical property parameters thereof are measured as follows: a bending strength of 783 MPa, a fracture toughness of 6.98 MPa·m 1 / 2 , and a Vickers hardness of 17.73 GPa.

[0096] Example 6

[0097] Different from example 3, the proportion of the ceramic matrix and the metal binder phase in step (2) is different. The specific steps are as follows:

[0098] The volume ratio of the ceramic matrix in the co-high-entropy carbide cermet material is 85%, the volume ratio of the metal binder phase is 15%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1.

[0099] The preparation method of the co-high-entropy carbide cermet material comprises the following steps:

[0100] (1) Take anhydrous ethanol into a beaker, weigh and add polyethylene glycol, place the beaker in a water bath, and magnetically stir at 55°C for 10 min until the polyethylene glycol is completely dissolved, and then cool to room temperature to prepare a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2 g / L;

[0101] (2) mixing powders according to the volume ratio of 85% of ceramic matrix, 15% of metal binder phase, the molar ratio of each carbide in the matrix being 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase being 1:1:1:1:1, adding the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1) into the mixture, ultrasonic dispersion for 60 min and mechanical stirring to prepare a mixed solution; the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the sum of the masses of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder and Ti powder;

[0102] (3) placing the prepared mixed solution in a ball mill tank, using cemented carbide balls as grinding balls, the cemented carbide balls being mixed cemented carbide balls with diameters of 5 mm and 10 mm, the mass ratio of the cemented carbide balls with diameters of 5 mm and 10 mm being 2:3, and the mass ratio of the balls to the material being 10:1, high-energy ball milling for 48 h under a nitrogen protective atmosphere;

[0103] (4) vacuum constant temperature drying of the ball-milled slurry at 120℃ for 48 h, sieving through a 200-mesh screen to prepare a mixed powder of the co-high-entropy carbide cermets;

[0104] (5) placing the mixed powder of the co-high-entropy carbide cermets in a graphite mold, discharging plasma coupling high-frequency induction sintering under a vacuum atmosphere, the sintering temperature being 1450℃, the sintering pressure being 30 MPa, the heating rate being preheating to 570℃, and heating to 600℃ within 1 min, heating to 900℃ at a rate of 100℃ / min, heating to 1250℃ at a rate of 75℃ / min, and heating to the target temperature at a rate of 50℃ / min, the holding time being 10 min, to prepare a co-high-entropy carbide cermet material. The prepared ceramic material sample is cut and processed, and the mechanical property parameters thereof are measured to be: a bending strength of 794 MPa, a fracture toughness of 7.15 MPa·m 1 / 2 , and a Vickers hardness of 17.93 GPa.

[0105] Example 7

[0106] Different from example 3, the proportions of the ceramic matrix and the metal binder phase in step (2) are different. The specific steps are as follows:

[0107] The volume ratio of the ceramic matrix in the co-high-entropy carbide cermet material is 80%, the volume ratio of the metal binder phase is 20%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase is 1:1:1:1:1.

[0108] The preparation method of the co-high-entropy carbide cermet material comprises the following steps:

[0109] (1) Take anhydrous ethanol into a beaker, weigh and add polyethylene glycol, put the beaker into a water bath, and magnetically stir at 55℃ for 10 min until the polyethylene glycol is completely dissolved, and then cool to room temperature to prepare a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2 g / L;

[0110] (2) Mix the powders according to the volume ratio of the ceramic matrix of 80%, the volume ratio of the metal binder phase of 20%, the molar ratio of each carbide in the matrix of 1:1:1:1:1, and the molar ratio of each metal in the metal binder phase of 1:1:1:1:1, add the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonic dispersion for 60 min and mechanical stirring to prepare a mixed solution; the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the mass sum of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder;

[0111] (3) Put the prepared mixed solution into a ball milling tank, use cemented carbide balls as the grinding balls, the cemented carbide balls are mixed cemented carbide balls with a diameter of 5 mm and a diameter of 10 mm, the mass ratio of the cemented carbide balls with a diameter of 5 mm and 10 mm is 2:3, and the ball-to-material mass ratio is 10:1, high-energy ball mill for 48 h under a nitrogen protective atmosphere;

[0112] (4) Dry the ball-milled slurry at 120℃ for 48 h under vacuum constant temperature, and sieve through a 200 mesh sieve to prepare a co-high-entropy carbide cermet mixed powder;

[0113] (5) Put the co-high-entropy carbide cermet mixed powder into a graphite mold and perform discharge plasma coupled high-frequency induction sintering under vacuum atmosphere, the sintering temperature is 1450℃, the sintering pressure is 30 MPa, the heating rate is: preheating to 570℃, and then heating to 600℃ within 1 min; heating to 900℃ at a rate of 100℃ / min; heating to 1250℃ at a rate of 75℃ / min; heating to the target temperature at a rate of 50℃ / min, and holding for 10 min to prepare a co-high-entropy carbide cermet material. Cut the prepared ceramic material sample and measure its mechanical property parameters: bending strength 774 MPa, fracture toughness 7.09 MPa·m 1 / 2 , Vickers hardness 17.65 GPa.

[0114] Comparative Example 1

[0115] The comparative example is the same as example 2, but the volume ratio of the ceramic matrix in step (2) is 100%, the volume ratio of the metal binder phase is 0%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the other preparations are the same as example 2. The prepared ceramic material sample is cut and processed, and the mechanical property parameters are measured as follows: bending strength 675.1 MPa, fracture toughness 5.96 MPa·m 1 / 2 , Vickers hardness 17.76 GPa.

[0116] Comparative example 2

[0117] The comparative example is the same as example 3, but the volume ratio of the ceramic matrix in step (2) is 100%, the volume ratio of the metal binder phase is 0%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the other preparations are the same as example 3. The prepared ceramic material sample is cut and processed, and the mechanical property parameters are measured as follows: bending strength 746.64 MPa, fracture toughness 6.32 MPa·m 1 / 2 , Vickers hardness 16.57 GPa.

[0118] Comparative example 3

[0119] The comparative example is the same as example 4, but the volume ratio of the ceramic matrix in step (2) is 100%, the volume ratio of the metal binder phase is 0%, the molar ratio of each carbide in the matrix is 1:1:1:1:1, and the other preparations are the same as example 4. The prepared ceramic material sample is cut and processed, and the mechanical property parameters are measured as follows: bending strength 573.19 MPa, fracture toughness 6.19 MPa·m 1 / 2 , Vickers hardness 16.41 GPa.

[0120] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A co-high entropy carbide cermet material, characterized in that, It includes a matrix and a metal binder phase, with a high-entropy carbide as the matrix and a high-entropy alloy as the metal binder phase, wherein the matrix is ​​a high-entropy carbide (WVMoTaTi)C; The high-entropy carbides and high-entropy alloys contain the same metallic elements; in high-entropy carbides, the molar ratio of each carbide is the same; in high-entropy alloys, the molar ratio of each metallic element is the same. In co-high entropy carbide cermet materials, the matrix accounts for 80-95% of the volume, and the metal binder phase accounts for 5-20% of the volume.

2. The co-high entropy carbide cermet material according to claim 1, characterized in that, In co-high entropy carbide cermet materials, the matrix accounts for 88-92% of the volume, and the metal binder phase accounts for 8-12% of the volume.

3. A method for preparing a co-high entropy carbide cermet material as described in claim 1 or 2, characterized in that, Includes the following steps: S1. According to the set ratio, mix WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, Mo powder, Ta powder, and Ti powder to obtain a raw material mixture, and place it in a polyethylene glycol-anhydrous ethanol dispersion to obtain a mixed solution. S2. The mixed solution is ball-milled, dried, and sieved to obtain a mixed powder; S3. The mixed powder is subjected to discharge plasma coupling high-frequency induction sintering to obtain the final product.

4. The preparation method according to claim 3, characterized in that, In step S1, polyethylene glycol is added to anhydrous ethanol and stirred in a water bath at a constant temperature. The mixture is then cooled to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion. The molecular weight of the polyethylene glycol is 5000~7000; In the polyethylene glycol-anhydrous ethanol dispersion, the concentration of polyethylene glycol is 2~4 g / L; The water bath temperature is 55~65℃, and magnetic stirring is used for stirring for 10-15 minutes.

5. The preparation method according to claim 3, characterized in that, In step S1, the mass of polyethylene glycol is 0.09% to 1.1% of the total mass of the raw material mixture; In step S1, the average particle size of WC powder, VC powder, Mo2C powder, TaC powder, TiC powder, W powder, V powder, and Ta powder is 1~3μm, and the average particle size of Mo powder and Ti powder is 0.8~1.2μm.

6. The preparation method according to claim 3, characterized in that, In step S2, the ball milling process is as follows: the mixed solution and grinding balls are poured into a tank, the total mass of the raw material mixture is 1:(8~20) of the weight of the grinding balls, and the mixture is ball milled for 45~50 hours under a protective atmosphere.

7. The preparation method according to claim 6, characterized in that, The protective atmosphere for the ball mill is nitrogen. The grinding balls are a mixture of 5mm and 10mm diameter cemented carbide grinding balls with a mass ratio of (1~2):(1~5).

8. The preparation method according to claim 3, characterized in that, In step S3, the mixed powder is placed in a graphite mold and subjected to high-frequency induction sintering via discharge plasma coupling under a vacuum atmosphere. The conditions for discharge plasma coupling high-frequency induction sintering are as follows: sintering temperature: 1350~1500℃; sintering pressure: 30~40MPa; heating rate: preheat to 565~575℃ and then heat to 595~605℃ within 1 min; heat to 895~905℃ at 95~105℃ / min; heat to 1245~1255℃ at 70~80℃ / min; heat to the target temperature at 45~55℃ / min; and hold for 8~12 min.

9. The preparation method according to claim 8, characterized in that, Sintering temperature: 1430~1470℃.

10. The application of a co-high entropy carbide cermet material according to claim 1 or 2, or a co-high entropy carbide cermet material obtained by the preparation method according to any one of claims 3 to 9, in the fields of high-precision machining, high-speed or ultra-high-speed cutting.

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