Titanium-based metal ceramic material with high-entropy alloy as bonding phase and preparation method of titanium-based metal ceramic material

Abstract

A titanium-based metal ceramic material with a six-element high-entropy alloy as a bonding phase is prepared by taking Ti-CN as a hard phase, the six-element high-entropy alloy as the bonding phase and Mo2C as a strengthening phase through mixing, ball milling, pretreatment, pre-press forming and high-temperature sintering in sequence, and according to the mass percent, the mass ratio of Ti-CN is 50-60%, the mass ratio of the six-element high-entropy alloy is 30-45%, and the mass ratio of Mo2C is 5-10%. According to the Ti-CN-based metal ceramic and the preparation method thereof, the ball-milled powder is pretreated through combination of electric field assistance and low-temperature pre-sintering, the overall performance of the metal ceramic obtained after SPS is effectively improved, the hardness of the prepared Ti-CN-based metal ceramic reaches HV1920, the fracture toughness reaches 15.9 MPa.m / , the bending strength reaches 2400 Mpa, the Ti-CN-based metal ceramic has excellent wear resistance and corrosion resistance, the wear rate is as low as 1.2 * 10 <-7 > mm < 3 > / N.m, and the service life of the Ti-CN-based metal ceramic is prolonged. The corrosion rate is as low as 0.0012 g / (m < 2 >. H).

Description

Technical Field

[0001] The present invention relates to the technical field of metal ceramic material preparation, and in particular to a titanium-based metal ceramic material with a hexavalent high entropy alloy as a bonding phase and a preparation method thereof. Background Art

[0002] Traditional titanium-based cermets are typically manufactured with a single or a few elements as additives and a Ni / Co binder phase. However, their performance improvements face bottlenecks. For example, in terms of hardness, they struggle to meet the demands of applications such as high-hardness cutting tools. In terms of toughness, they are prone to brittle fracture under impact loads, limiting their use in complex working conditions. For example, traditional binders (such as Ni and Co) soften easily at high temperatures, resulting in a significant decrease in the material's strength and hardness. Ti-CN-based cermets are susceptible to interfacial oxidation in high-temperature oxidizing environments, forming a loose oxide layer that accelerates material failure. Furthermore, traditional binders offer limited resistance to corrosive media, making them difficult to meet the demands of complex working conditions. The Co / Ni binder phase has poor wettability with the Ti(C,N) ceramic phase, resulting in a weak interfacial bond after sintering. This makes the material susceptible to chipping or delamination when subjected to impact or thermal stress, and its toughness and flexural strength struggle to meet the requirements of high-end applications. With the continuous improvement of modern industry's requirements for material performance, such as the aerospace field's comprehensive demand for lightweight materials with high strength and high toughness, and the electronics field's requirement for high conductivity and stability of materials, existing titanium-based metal ceramic materials are difficult to meet these harsh conditions in terms of comprehensive performance.

[0003] High entropy alloys are composed of more than five metal / non-metal elements. Due to their unique multi-principal component design, they have the advantages of high strength, high hardness, good wear resistance and corrosion resistance, and have gradually attracted attention. However, there are relatively few studies on applying the concept of high entropy alloys to titanium-based metal ceramic materials, and there are still many challenges in the preparation process and performance optimization. Metal ceramics need to have both high hardness (dependent on Ti-CN) and a certain toughness (dependent on the binder phase). High entropy ceramics have advantages in hardness, oxidation resistance, etc., but the multi-component characteristics of high entropy alloys also make their interface reaction with TiCN more complicated, and their complex multi-component composition can easily lead to local component segregation, forming low entropy phases or brittle intermetallic compounds, destroying the continuity of the binder phase, and causing the mechanical properties of the material to deteriorate. In addition, the thermal expansion coefficient of Ti-CN (CTE, about 7~9×10 -6 / ℃) has a large difference in CTE with high-entropy alloys, which will generate significant internal stress during sintering and cooling, leading to microcracks or interface peeling.

[0004] In addition, the multi-component nature of high-entropy alloys leads to high raw material costs, and slight fluctuations in the proportion of components may have a significant impact on the overall performance of the material. Summary of the Invention

[0005] Based on the above technical problems, the present invention aims to provide a titanium-based metal ceramic material with a hexavalent high entropy alloy as a bonding phase.

[0006] Another object of the present invention is to provide a method for preparing the aforementioned titanium-based cermet material. Through unique element design and microstructural manipulation during the preparation process, the material exhibits excellent overall properties, including high hardness, high toughness, and excellent wear and corrosion resistance, thereby meeting the demands of modern industry for high-performance materials.

[0007] The purpose of the present invention is achieved through the following technical solutions: A titanium-based cermet material with a six-element high-entropy alloy as a bonding phase is characterized in that: Ti-CN is used as a hard phase, the six-element high-entropy alloy is used as a bonding phase, and Mo2C is used as a strengthening phase. The material is prepared by sequentially undergoing mixed ball milling, pretreatment, pre-pressing and high-temperature sintering. In terms of mass percentage, the mass proportion of Ti-CN is 50-60%, the mass proportion of the six-element high-entropy alloy is 30-45%, and the mass proportion of Mo2C is 5-10%.

[0008] Furthermore, the hexavalent high entropy alloy is composed of Cr, Fe, Co, Al, V and Ta, with the atomic percentage being 24-26% Cr, 22-25% Fe, 15-20% Co, 15-18% Al, 7-9% V and 7-9% Ta.

[0009] Furthermore, the pretreatment is a two-step pretreatment, the first step is electric field assisted pretreatment, specifically applying a DC electric field of 200~350V / cm to the ball milled powder and treating it at 200~400℃ for 20~30min, and the second step is low-temperature pre-calcination treatment, specifically low-temperature pre-calcination treatment at 600~700℃ for 30~50min.

[0010] Furthermore, the high-temperature sintering is spark plasma sintering, specifically, the green body is placed in a graphite mold and sintered in a vacuum environment, firstly raised to 1000-1200°C at 20-30°C / min and kept warm for 10-15 minutes, with a sintering pressure of 15-25 MPa, then raised to 1300-1450°C at 50-60°C / min, kept warm for 5-10 minutes, with a sintering pressure of 40-50 MPa.

[0011] A method for preparing a titanium-based cermet material with a hexavalent high-entropy alloy as a bonding phase is characterized by: using Ti-CN as a hard phase, a hexavalent high-entropy alloy as a bonding phase, and Mo2C as a strengthening phase through mixed ball milling to obtain ball-milled powder, pre-treating the ball-milled powder, then pre-pressing and forming it, and finally performing spark plasma sintering. The pre-treatment comprises sequentially performing electric field-assisted pre-treatment and low-temperature pre-sintering treatment on the ball-milled powder.

[0012] Furthermore, the hexavalent high entropy alloy is composed of Cr, Fe, Co, Al, V and Ta, with the atomic percentage being 24-26% Cr, 22-25% Fe, 15-20% Co, 15-18% Al, 7-9% V and 7-9% Ta.

[0013] Furthermore, in terms of mass percentage, the mass proportion of Ti-CN is 50~60%, the mass proportion of the hexavalent high entropy alloy is 30~45%, and the mass proportion of Mo2C is 5~10%.

[0014] Furthermore, the electric field assisted pretreatment is to apply a DC electric field of 200-350 V / cm to the ball milled powder and treat it at 200-400° C. for 20-30 minutes.

[0015] Furthermore, the low-temperature pre-sintering treatment is performed at a temperature between 600° C. and 700° C. for 30 to 50 minutes.

[0016] Furthermore, the mixed ball milling is to weigh Ti-CN powder and metal powders or metal oxide powders corresponding to six high entropy elements according to the stoichiometric ratio, add them into a ball mill, use anhydrous ethanol as the ball milling medium, the ball-to-material ratio is 10:1, the ball milling speed is 300~500r / min, the ball milling time is 24~48h, and then vacuum drying is performed to obtain a uniformly mixed ball-milled powder.

[0017] Furthermore, the pre-pressing molding is to pre-press the pretreated powder under a pressure of 100-200 MPa to form a green body.

[0018] Furthermore, the spark plasma sintering is to place the green body into a graphite mold and sinter it in a vacuum environment, first raising the temperature to 1000-1200°C at 20-30°C / min and keeping it for 10-15 minutes, with a sintering pressure of 15-25 MPa, then raising the temperature to 1300-1450°C at 50-60°C / min, keeping it for 5-10 minutes, with a sintering pressure of 40-50 MPa.

[0019] The high-entropy alloy used in the present invention has multiple strengthening mechanisms, and solid solution strengthening (Al, V, Ta), precipitation strengthening (V, Ta carbides) and grain refinement (Fe, Cr) jointly improve the strength and toughness of the material.

[0020] Ti-CN, as a hard phase, is easily oxidized to form TiO2 and CO / NO at high temperatures (>800℃) x , leading to surface peeling and performance degradation. The high activity of Al causes it to react with oxygen before elements such as Ti and Cr, forming a dense Al2O3 oxide film at a lower temperature (melting point 2072°C, thermal expansion coefficient close to that of Ti-CN). Cr oxidizes at high temperatures to form Cr2O3, which forms a double-layer oxide film with Al2O3, effectively blocking oxygen diffusion into the interior and protecting Ti-CN particles from oxidation. However, during SPS sintering, the low-melting-point Al melts prematurely and migrates, while other high-melting-point elements remain in the solid state, resulting in local component enrichment (such as Al clusters) and the formation of an uneven microstructure. At the same time, Al easily forms brittle phases (such as Al4C3, Al2O3, FeAl3, etc.) with C (from Ti-CN), O (environmental or powder impurities), or other metals (such as Cr, Fe), resulting in a decrease in interfacial bonding strength and deterioration of material toughness.

[0021] Good wettability between the binder phase and the hard phase (Ti-CN) is a prerequisite for ensuring the density and mechanical properties of cermets. If wettability is poor, the high-entropy alloy cannot effectively fill the interstices between the Ti-CN particles, easily forming pores. As a transition metal, Fe has a surface energy (approximately 2.9 J / m²) that closely matches that of Ti-CN (approximately 3.1 J / m²). Its addition can reduce the interfacial energy between the high-entropy alloy and Ti-CN, thereby improving the density of the cermet. However, Fe has a high diffusion coefficient and easily penetrates the Ti-CN hard phase, leading to hard phase decomposition (e.g., replacement of Ti in Ti-CN with Fe) or the formation of brittle intermetallic compounds (e.g., Fe-Ti phases), which compromise the integrity of the hard phase.

[0022] The wettability of the Ti-CN ceramic phase (surface energy of approximately 1.2-1.5 J / m²) with the high-entropy alloy binder phase is extremely poor, which directly leads to the difficulty of the metal phase spreading on the Ti-CN surface during sintering and low interfacial bonding strength.

[0023] To address these issues, the present invention performs an electric field-assisted pretreatment on the ball-milled powder before compaction. This process utilizes low-temperature energy activation and electric field-directed drive to induce the directional segregation and enrichment of high-entropy alloy elements on the surface of Ti-CN particles, utilizing differences in elemental electronegativity. This is followed by a low-temperature pre-sintering treatment, which promotes the preferential reaction of Al with N to form an AlN barrier, blocking the reaction between Al and C. The AlN acts as a transition layer, improving the lattice matching between the bonding phase and the hard phase, thereby enhancing interfacial bonding strength. Furthermore, because the electronegativity of Al, Cr, V, and Ta in the high-entropy alloy is relatively low and close, an atomic-level contact interface is formed under the action of electric field polarization. During low-temperature pre-sintering, this interface preferentially reacts and diffuses at a lower temperature, generating stable and uniformly distributed intermetallic compounds. This prevents the formation of a brittle phase from reacting with the hard phase during the SPS process, while also limiting the diffusion of Fe. The electric field changes the diffusion direction of Fe through the "electromigration effect". As a transition metal, Fe is easily enriched in the electric field to form a local low-energy zone, and its diffusion power to the Ti-CN interface is weakened. At the same time, Fe and Co have similar electronegativity. After the two are enriched under the action of the electric field, an Fe-Co solid solution is formed during the pre-sintering treatment, which further inhibits the diffusion of Fe into the body.

[0024] A method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase, characterized by comprising the following steps: S1. Composition design: Based on mass percentage, Ti-CN is the hard phase, accounting for 50-60% by mass, the high-entropy alloy is the binder phase, accounting for 30-45% by mass, and Mo2C is the strengthening phase, accounting for 5-10% by mass. The high-entropy alloy is CrFeCoAlVTa, and the atomic percentages are 24-26% Cr, 22-25% Fe, 15-20% Co, 15-18% Al, 7-9% V, and 7-9% Ta. S2. Mixing ball milling: Ti-CN powder and metal powders or metal oxide powders corresponding to six high entropy elements are weighed according to a stoichiometric ratio and added to a ball mill. Anhydrous ethanol is used as a ball milling medium with a ball-to-material ratio of 10:1, a ball milling speed of 300-500 r / min, and a ball milling time of 24-48 hours. The ball mill is then vacuum dried to obtain a uniformly mixed ball-milled powder, wherein the Ti-CN powder has a purity of ≥99% and a particle size of 1-5 μm; the metal powder has a purity of ≥99% and a particle size of 2-8 μm; and the metal oxide powder has a purity of ≥99% and a particle size of 3-10 μm. S3. Ball-milled powder pretreatment: This pretreatment step consists of two steps. The first step involves applying a DC electric field of 200-350 V / cm to the ball-milled powder at 200-400°C for 20-30 minutes. The second step involves low-temperature calcination at 600-700°C for 30-50 minutes to obtain the pretreated powder. S4 pre-pressing: The pretreated powder is pre-pressed under a pressure of 100 - 200MPa to form a green body; S5. Sintering treatment: Using the spark plasma sintering (SPS) process, the green body is placed in a graphite mold and sintered in a vacuum environment. First, the temperature is raised to 1000-1200℃ at 20-30℃ / min and kept at this temperature for 10-15 minutes. The sintering pressure is 15-25Mpa. Then, the temperature is raised to 1300-1450℃ at 50-60℃ / min and kept at this temperature for 5-10 minutes. The sintering pressure is 40-50Mpa.

[0025] During the SPS process, the transitional AlN phase forms a buffer layer, reducing direct reactions between the hard and binder phases. During the staged SPS process, the first stage effectively prevents binder phase aggregation, regulates the interfacial reaction rate and uniform diffusion of components, and allows the binder phase and Ti-CN hard phase to form a uniform and stable interface under controlled diffusion. The second stage achieves rapid densification and prevents abnormal growth of the hard phase. This two-step SPS process reduces the internal temperature gradient of the green body, thereby alleviating stress concentration.

[0026] The present invention has the following technical effects: In the present invention, the ball-milled powder is pretreated by combining electric field assistance with low-temperature pre-sintering, which effectively improves the overall performance of the metal ceramic after SPS. The prepared Ti-CN-based metal ceramic has a hardness of HV1920, a fracture toughness of 15.9 MPa·m¹ / ², and a bending strength of 2400 MPa. It has excellent wear resistance and corrosion resistance, and the wear rate is as low as 1.2×10 -7 mm 3 / N·m, the corrosion rate is as low as 0.0012 g / (m 2 ·h). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : Composition energy spectrum of the Ti-CN based metal ceramic material prepared in Example 1.

[0028] Figure 2 : SEM image of the ball-milled powder after pretreatment in Example 1.

[0029] Figure 3 : SEM microstructure of the Ti-CN based metal ceramic material prepared in Example 1.

[0030] Figure 4 : Hardness uniformity test results of the Ti-CN based cermet material prepared in Example 1. DETAILED DESCRIPTION

[0031] The present invention is described in detail below through examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above-mentioned contents of the present invention.

[0032] Example 1 A method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase comprises the following steps: S1. Composition design: Based on mass percentage, Ti-CN is the hard phase, accounting for 55% by mass, the high-entropy alloy is the binder phase, accounting for 38% by mass, and Mo2C is the strengthening phase, accounting for 7% by mass. The high-entropy alloy is CrFeCoAlVTa, with the atomic number percentages of Cr (25%), Fe (23%), Co (19%), Al (17%), V (8%), and Ta (8%). S2. Mixing ball milling: Ti-CN powder and metal powders or metal oxide powders corresponding to six high entropy elements were weighed in a stoichiometric ratio and added to a ball mill. Anhydrous ethanol was used as the ball milling medium, the ball-to-material ratio was 10:1, the ball milling speed was 400 r / min, the ball milling time was 36 h, and then vacuum dried to obtain a uniformly mixed ball-milled powder. The Ti-CN powder had a purity of ≥99% and a particle size of 1-5 μm; the metal powder had a purity of ≥99% and a particle size of 2-8 μm; and the metal oxide powder had a purity of ≥99% and a particle size of 3-10 μm. S3. Ball-milled powder pretreatment: This pretreatment step consists of two steps. The first step involves applying a 300 V / cm DC electric field to the ball-milled powder at 300°C for 25 minutes. The second step involves low-temperature calcination at 650°C for 40 minutes to obtain the pretreated powder. S4 pre-pressing: The pretreated powder is pre-pressed under a pressure of 150MPa to form a green body; S5. Sintering treatment: Using the spark plasma sintering (SPS) process, the green body is placed in a graphite mold and sintered in a vacuum environment. First, the temperature is raised to 1100℃ at 25℃ / min and kept for 12 minutes. The sintering pressure is 20 MPa. Then, the temperature is raised to 1400℃ at 55℃ / min and kept for 6 minutes. The sintering pressure is 45 MPa.

[0033] The SEM image of the pretreated powder prepared in this embodiment is as follows Figure 2shown.

[0034] The microstructure of the metal ceramic material prepared in this embodiment is as follows Figure 3 As shown, it can be seen that the surface of the material is evenly distributed and the structure is dense, without cracks, holes and other phenomena.

[0035] Comparative Example 1 Compared with Example 1, after the mixing and ball milling, the pretreatment of the powder is only the first step of pretreatment, without the second step of pretreatment, and the remaining steps are the same as in Example 1.

[0036] Comparative Example 2 Compared with Example 1, after the mixing and ball milling, the powder was pretreated by only the second step of pretreatment, without the first step of pretreatment. The remaining steps were the same as in Example 1.

[0037] Comparative Example 3 Compared with Example 1, after the mixing and ball milling, the pretreatment of the powder is only the first step of pretreatment. After pre-pressing and molding, the second step of pretreatment is performed. The remaining steps are the same as in Example 1.

[0038] Product performance test: Various properties of the metal ceramic materials prepared in Example 1 and various comparative examples were tested.

[0039] (1) Hardness test: Vickers hardness testing is performed according to GB / T 4340.1-2009, "Metallic Materials - Vickers Hardness Test - Part 1: Test Method." Using a Vickers hardness tester, apply a load (98.07N) and hold for 10-15 seconds to create an indentation on the material surface. The diagonal length of the indentation is measured, and the Vickers hardness value (HV) is calculated using the following formula:

[0040] Where HV is the Vickers hardness value (in kilograms-force per square millimeter, kgf / mm²); F is the test load (in kilograms-force, kgf); and d is the arithmetic mean of the two diagonal lengths of the indentation (in millimeters, mm). To ensure data accuracy, perform at least five tests at different locations on the material, and take the average value as the material's hardness value.

[0041] (2) Fracture toughness test: The test was conducted in accordance with GB / T 2358-1994 "Metallic Materials Crack Tip Opening Displacement Test Method". The material was processed into a standard compact tensile specimen and loaded on a universal material testing machine. By measuring the load-displacement curve during the crack propagation process, the fracture toughness value (K) of the material was calculated using the following formula: IC):

[0042] in, : Conditional critical load (unit: N); B: Specimen thickness (unit: mm); W: Specimen width (the distance from the center of the loading hole to the edge of the specimen, unit: mm); : Crack length (the distance from the crack tip to the center of the loading hole, unit: mm). To ensure data accuracy, at least five tests were performed at different locations on the material, and the average value was taken as the fracture toughness value of the material.

[0043] (3) Strength test: The flexural strength test follows the standard GB / T 38514-2020 "Determination of transverse fracture strength of cemented carbide". The material is processed into a standard bending specimen (such as a rectangular three-point bending specimen), loaded at a specified rate on a universal material testing machine, and the maximum load at fracture is recorded. The flexural strength is calculated according to the formula ( ):

[0044] Where F is the maximum load at break, L is the span, b is the specimen width, and h is the specimen thickness. Five parallel tests were performed and the average value was taken to ensure data representativeness.

[0045] (4) Wear resistance test Wear resistance testing was conducted using a pin-on-disc wear tester. Pin-shaped specimens were prepared and subjected to friction testing against a rotating disc specimen (made of GCr15 steel) under a constant load (50N) and rotational speed (200 rpm). During the test, the volume loss of the pin specimen after sliding a certain distance was measured, and the wear rate was calculated using the following formula:

[0046] Δ V : Wear volume loss (unit: mm 3 ); F : normal load (unit: N); S : total sliding distance (unit: m); K : Wear rate (unit: mm 3 / N·m ).

[0047] (5) Corrosion resistance test Adopting national standard: GB / T 10124-2021 "Method for laboratory uniform corrosion immersion test of metal materials" Potentiodynamic polarization curve tests were performed using an electrochemical workstation in accordance with ASTM G5-94, Standard Practice for Potentiodynamic Polarization Measurements. The specimens were completely immersed in a specific corrosive medium (3.5% NaCl solution). The specimens were removed periodically, and loose corrosion products on the surface were removed with a soft brush (to avoid scratching the substrate). The specimens were then washed with deionized water, dehydrated with alcohol, and weighed after drying. mt ), the corrosion rate is calculated by the formula:

[0048] Where: v is the corrosion rate (unit: g / (m 2 h)); S is the surface area of ​​the sample (unit: m 2 ); t is the soaking time (unit: h).

[0049] The product performance test results are shown in Table 1, wherein the CK group is a metal ceramic prepared without any pretreatment of the ball-milled powder after ball milling compared to Example 1.

[0050] Table 1:

[0051] Compared to the CK group, which did not pretreat the ball-milled powder, the cermet prepared in Example 1, which pretreated the ball-milled powder, exhibited significantly increased hardness, toughness, and flexural strength, demonstrating excellent mechanical properties. Wear and corrosion resistance were also significantly improved. In Comparative Example 1, due to the segregation and enrichment of the high-entropy alloy after electric field-assisted pretreatment, the lack of subsequent low-temperature pre-sintering to promote reaction and diffusion resulted in a significant decrease in the toughness, strength, and other mechanical properties of the final product.

[0052] from Figure 4 It can be seen that the material prepared in Example 1 has excellent hardness uniformity.

[0053] Effects of different high entropy alloy compositions on the mechanical properties of materials: During the experiment, attempts were made to adjust the composition of the high-entropy alloy, specifically by using a five-element high-entropy alloy CrFeCoAlTa (i.e., removing V from the high-entropy alloy in Example 1), a six-element high-entropy alloy CrFeCoAlVNb (i.e., using Nb to completely replace Ta in the high-entropy alloy in Example 1), and a seven-element high-entropy alloy CrFeCoAlVTaNb (i.e., adding Nb to replace 50% Ta in the high-entropy alloy in Example 1) to replace the high-entropy alloy in Example 1 respectively. The influence of the composition of high entropy alloy on the mechanical properties of the final material is shown in Table 2.

[0054] Table 2:

[0055] As can be seen from the above table, under the preparation process of the present invention, the elemental composition of the high-entropy alloy bonding phase used has a significant impact on the performance of the final metal ceramic, and the high-entropy alloy composition CrFeCoAlVTa in the present invention effectively improves the hardness, toughness and other mechanical properties of the material at the same time, while adding other components or reducing the components on this basis will significantly reduce the mechanical properties of the material.

[0056] Example 2 A method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase comprises the following steps: S1. Composition design: Based on mass percentage, Ti-CN is the hard phase, accounting for 50% by mass, the high-entropy alloy is the binder phase, accounting for 45% by mass, and Mo2C is the strengthening phase, accounting for 5% by mass. The high-entropy alloy is CrFeCoAlVTa, and the atomic number percentages are 24% Cr, 25% Fe, 20% Co, 15% Al, 7% V, and 9% Ta. S2. Mixing ball milling: Ti-CN powder and metal powders or metal oxide powders corresponding to six high entropy elements were weighed in a stoichiometric ratio and added to a ball mill. Anhydrous ethanol was used as the ball milling medium, the ball-to-material ratio was 10:1, the ball milling speed was 500 r / min, the ball milling time was 24 h, and then vacuum dried to obtain a uniformly mixed ball-milled powder. The Ti-CN powder had a purity of ≥99% and a particle size of 1-5 μm; the metal powder had a purity of ≥99% and a particle size of 2-8 μm; and the metal oxide powder had a purity of ≥99% and a particle size of 3-10 μm. S3. Ball-milled powder pretreatment: The pretreatment is a two-step process. The first step involves applying a 200 V / cm DC electric field to the ball-milled powder at 400°C for 20 minutes. The second step involves low-temperature calcination at 700°C for 30 minutes to obtain the pretreated powder. S4 pre-pressing: The pretreated powder is pre-pressed under a pressure of 200MPa to form a green body; S5. Sintering treatment: Using the spark plasma sintering (SPS) process, the green body is placed in a graphite mold and sintered in a vacuum environment. First, the temperature is raised to 1200℃ at 20℃ / min and kept for 10 minutes. The sintering pressure is 15Mpa. Then, the temperature is raised to 1300℃ at 60℃ / min and kept for 10 minutes. The sintering pressure is 50Mpa.

[0057] After testing, the hardness of the metal ceramic product prepared in this embodiment reached HV1940, the fracture toughness was 15.6 MPa·m¹ / ², and the bending strength reached 2370 MPa.

[0058] Example 3 A method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase comprises the following steps: S1. Composition design: Based on mass percentage, Ti-CN is the hard phase, accounting for 60% by mass, the high-entropy alloy is the binder phase, accounting for 30% by mass, and Mo2C is the strengthening phase, accounting for 10% by mass. The high-entropy alloy is CrFeCoAlVTa, and the atomic percentages are 26% Cr, 20% Fe, 20% Co, 18% Al, 9% V, and 7% Ta. S2. Mixing ball milling: Ti-CN powder and metal powders or metal oxide powders corresponding to six high entropy elements were weighed in a stoichiometric ratio and added to a ball mill. Anhydrous ethanol was used as the ball milling medium, the ball-to-material ratio was 10:1, the ball milling speed was 300 r / min, the ball milling time was 48 h, and then vacuum dried to obtain a uniformly mixed ball-milled powder. The Ti-CN powder had a purity of ≥99% and a particle size of 1-5 μm; the metal powder had a purity of ≥99% and a particle size of 2-8 μm; and the metal oxide powder had a purity of ≥99% and a particle size of 3-10 μm. S3. Ball-milled powder pretreatment: This pretreatment step consists of two steps. The first step involves applying a 350 V / cm DC electric field to the ball-milled powder at 200°C for 30 minutes. The second step involves low-temperature calcination at 600°C for 50 minutes to obtain the pretreated powder. S4 pre-pressing: The pretreated powder was pre-pressed under a pressure of 100 MPa to form a green body; S5. Sintering treatment: Using spark plasma sintering (SPS) technology, the green body is placed in a graphite mold and sintered in a vacuum environment. First, the temperature is raised to 1000℃ at 30℃ / min and kept for 15 minutes. The sintering pressure is 25Mpa. Then, the temperature is raised to 1450℃ at 50℃ / min and kept for 5 minutes. The sintering pressure is 40Mpa.

[0059] According to tests, the hardness of the metal ceramic product prepared in this embodiment reaches HV1900, the fracture toughness is 15.8 MPa·m¹ / ², and the bending strength reaches 2350 MPa.

Claims

1. A titanium-based cermet material with a hexavalent high-entropy alloy as a bonding phase, characterized by: It is made of Ti-CN as the hard phase, hexa-element high entropy alloy as the bonding phase, and Mo2C as the strengthening phase, and is made through mixed ball milling, pretreatment, pre-pressing and high-temperature sintering. In terms of mass percentage, the mass proportion of Ti-CN is 50~60%, the mass proportion of hexa-element high entropy alloy is 30~45%, and the mass proportion of Mo2C is 5~10%.

2. The titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase according to claim 1, characterized in that: The hexavalent high entropy alloy is composed of Cr, Fe, Co, Al, V and Ta, with the atomic percentages being 24-26% for Cr, 22-25% for Fe, 15-20% for Co, 15-18% for Al, 7-9% for V and 7-9% for Ta.

3. The titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase according to claim 1 or 2, characterized in that: The pretreatment is a two-step pretreatment. The first step is electric field assisted pretreatment, specifically applying a DC electric field of 200~350V / cm to the ball milled powder and treating it at 200~400℃ for 20~30min. The second step is low-temperature pre-calcination treatment, specifically performing low-temperature pre-calcination treatment at 600~700℃ for 30~50min.

4. The titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase according to claim 3, characterized in that: The high-temperature sintering is spark plasma sintering, specifically, placing the green body in a graphite mold and sintering in a vacuum environment, first raising the temperature to 1000-1200°C at 20-30°C / min and keeping it for 10-15 minutes, with a sintering pressure of 15-25 MPa, then raising the temperature to 1300-1450°C at 50-60°C / min, keeping it for 5-10 minutes, with a sintering pressure of 40-50 MPa.

5. A method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase, characterized by: The method comprises the following steps: using Ti-CN as a hard phase, a hexavalent high entropy alloy as a bonding phase, and Mo2C as a strengthening phase to obtain ball-milled powder through mixed ball milling; pre-treating the ball-milled powder; pre-pressing the powder into a mold; and finally performing spark plasma sintering. The pre-treatment comprises sequentially performing electric field assisted pre-treatment and low-temperature pre-sintering treatment on the ball-milled powder.

6. The method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase according to claim 5, characterized in that: The hexavalent high entropy alloy is composed of Cr, Fe, Co, Al, V and Ta, with the atomic percentages being 24-26% for Cr, 22-25% for Fe, 15-20% for Co, 15-18% for Al, 7-9% for V and 7-9% for Ta.

7. The method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase according to claim 5 or 6, characterized in that: In terms of mass percentage, the mass proportion of Ti-CN is 50~60%, the mass proportion of hexavalent high entropy alloy is 30~45%, and the mass proportion of Mo2C is 5~10%.

8. A method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase according to any one of claims 5 to 7, characterized in that: The electric field assisted pretreatment is to apply a DC electric field of 200-350 V / cm to the ball milled powder and treat it at 200-400° C. for 20-30 minutes. The low temperature pre-sintering treatment is to perform a low temperature pre-sintering treatment at 600-700° C. for 30-50 minutes.

9. The method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase according to any one of claims 5 to 8, characterized in that: The spark plasma sintering is to place the green body into a graphite mold and sinter it in a vacuum environment. The temperature is first raised to 1000-1200°C at 20-30°C / min and kept for 10-15 minutes at a sintering pressure of 15-25 MPa. Then the temperature is raised to 1300-1450°C at 50-60°C / min and kept for 5-10 minutes at a sintering pressure of 40-50 MPa.

10. A method for preparing a titanium-based cermet material with a hexavalent high entropy alloy as a bonding phase, characterized in that: The steps include: S1. Composition design: Based on mass percentage, Ti-CN is the hard phase, accounting for 50-60% by mass, the high-entropy alloy is the binder phase, accounting for 30-45% by mass, and Mo2C is the strengthening phase, accounting for 5-10% by mass. The high-entropy alloy is CrFeCoAlVTa, and the atomic percentages are 24-26% Cr, 22-25% Fe, 15-20% Co, 15-18% Al, 7-9% V, and 7-9% Ta. S2. Mixing ball milling: Ti-CN powder and metal powders or metal oxide powders corresponding to six high entropy elements are weighed according to a stoichiometric ratio and added to a ball mill. Anhydrous ethanol is used as a ball milling medium with a ball-to-material ratio of 10:1, a ball milling speed of 300-500 r / min, and a ball milling time of 24-48 hours. The ball mill is then vacuum dried to obtain a uniformly mixed ball-milled powder, wherein the Ti-CN powder has a purity of ≥99% and a particle size of 1-5 μm; the metal powder has a purity of ≥99% and a particle size of 2-8 μm; and the metal oxide powder has a purity of ≥99% and a particle size of 3-10 μm. S3. Ball-milled powder pretreatment: This pretreatment step consists of two steps. The first step involves applying a DC electric field of 200-350 V / cm to the ball-milled powder at 200-400°C for 20-30 minutes. The second step involves low-temperature calcination at 600-700°C for 30-50 minutes to obtain the pretreated powder. S4 pre-pressing: The pretreated powder is pre-pressed under a pressure of 100~200MPa to form a green body; S5. Sintering treatment: Using the spark plasma sintering (SPS) process, the green body is placed in a graphite mold and sintered in a vacuum environment. First, the temperature is raised to 1000-1200℃ at 20-30℃ / min and kept at this temperature for 10-15 minutes. The sintering pressure is 15-25MPa. Then, the temperature is raised to 1300-1450℃ at 50-60℃ / min and kept at this temperature for 5-10 minutes. The sintering pressure is 40-50MPa.

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