In-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet materials and preparation methods

Abstract

The present invention belongs to the field of metal processing, and relates to an in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material and a preparation method thereof. The present invention uses Ti(C, N) ceramic as the matrix, and directly adds Ni, Mo, Co, Al, and Ti as binders and sintered by spark plasma coupling high-frequency induction. The preparation method is to first mix Ti(C, N), Ni, Mo, Co, Al, and Ti, and then obtain the powder through ball milling and drying, and use spark plasma coupling high-frequency induction sintering. This method is beneficial to improving the mechanical properties of the material, saving the preparation time of high-entropy alloy powder, and has the advantages of simple preparation method and convenient operation. The obtained titanium carbonitride-based cermet has higher toughness, hardness, and excellent antifriction and wear resistance, and can be used to manufacture high-precision CNC machine tool guides and other wear-resistant and corrosion-resistant components.

Description

Technical Field

[0001] The present invention belongs to the field of metal processing, and relates to an in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material and a preparation method thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention, and it is not necessarily regarded as an admission or an indication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Ceramic materials have excellent thermal stability and wear resistance, and are ideal materials for manufacturing the guide rails of high-precision CNC machine tools. Most of the currently applied ceramic guide rail materials are limited to ceramics based on Al2O3, and the mechanical properties of the materials, especially the strength and toughness, still need to be further improved. Therefore, the research and development of ceramic guide rail materials with high strength and high toughness is one of the main directions for the future development of ceramic guide rail materials.

[0004] Cermet materials mainly include ceramics formed by sintering with various oxides, carbides and nitrides such as Al2O3, (W,Ti)C, Ti(C,N) as the matrix and adding transition metal elements such as Co, Ni, Cr, W, Mo, and all have better mechanical properties than single ceramic materials.

[0005] From the domestic and foreign status quo, the types of ceramic materials applied to the manufacture of high-precision machine tool guide rails are not many. At present, the application research of ceramic materials in various guide rails is mostly divided into several types, such as Al2O3 ceramics applied to ultra-precision machining and ultra-precision measurement, Si3N4 ceramics applied to high-precision CNC machine tools, etc. There is a research disclosure of a high-temperature oxidation-resistant titanium carbonitride cermet based on a high-entropy alloy binder, which is obtained by ball milling and mixing titanium carbonitride, carbide, Al x CoCrFeNiTi high-entropy alloy powder, etc., and then spark plasma sintering. However, its preparation method is complex and the mechanical properties still need to be improved. Therefore, there is an urgent need to develop a better metal processing method to meet the performance requirements of cermet materials. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a titanium carbonitride-based cermet material with better comprehensive mechanical properties and a preparation method thereof. The present invention omits the process of separately preparing high-entropy alloy powder, uses Ni, Mo, Co, Al, Ti as toughening phases and conducts high-energy ball milling (planetary type) with titanium carbonitride powder to directly form a high-entropy alloy, and then sinter it by spark plasma coupling high-frequency induction. The obtained cermet material has high bending strength, good thermal stability, excellent oxidation resistance and wear resistance, good toughness, and excellent resistance to sudden cooling and heating.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In the first aspect of the present invention, a preparation method of an in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material is provided, including:

[0009] Mix Ti(C,N) powder with Ni powder, Mo powder, Co powder, Al powder, and Ti powder evenly, disperse them into a polyethylene glycol-anhydrous ethanol dispersion liquid, perform wet ball milling, drying, and sieving to obtain a high-entropy alloy toughened titanium carbonitride cermet mixed powder;

[0010] Perform spark plasma coupled with high-frequency induction sintering on the high-entropy alloy toughened titanium carbonitride cermet mixed powder under vacuum conditions to obtain the product;

[0011] Among them, the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material is composed of the following components by mass percentage: Ti(C,N) 80-95%, Ni 1-4%, Mo 1-4%, Co 1-4%, Al 1-4%, Ti 1-4%, and the sum of the percentages of each component is 100%.

[0012] In the second aspect of the present invention, an in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material prepared by the above method is provided.

[0013] Advantages of the present invention

[0014] (1) In the present invention, Ni, Mo, Co, Al, and Ti are used as toughening phases and mixed with titanium carbonitride powder. After ball milling and vacuum drying, a sintering precursor of the cermet material is obtained, omitting the process of separately preparing high-entropy alloy powder.

[0015] (2) In the early stage of the present invention, through ultrasonic dispersion, high-energy ball milling, and constant-temperature drying, a mixed powder is obtained. Then, spark plasma coupled with 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°C. By forming a multi-component solid solution of molybdenum element and titanium carbonitride and enhancing the grain boundary bonding by high-entropy alloy, the problems of low strength and poor toughness of titanium carbonitride ceramic materials are overcome, and the comprehensive mechanical properties are significantly improved. Compared with existing ceramic guide rail materials, this cermet material has higher toughness, hardness, and excellent anti-friction and wear-resistant properties, and can be used to manufacture high-precision CNC machine tool guide rails and other wear-resistant and corrosion-resistant components.

[0016] (3) The present invention uses Ti(C,N) ceramics as the matrix, and adds Ni, Mo, Co, Al, and Ti as binders and is sintered by spark plasma coupling high-frequency induction. The obtained ceramic material specimens are cut and processed, and the measured mechanical property parameters are: flexural strength 957 - 1503 MPa, fracture toughness 9.4 - 11.5 MPa∙m 1 / 2 , and hardness 13.43 - 15.66 GPa. Description of the Drawings

[0017] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0018] Figure 1 is the characterization analysis of the high-entropy alloy toughened metal ceramic material prepared in Example 3: (a) NiMoCoAlTi electron microscope image, (b) elemental analysis diagram of Ni, (c) elemental analysis diagram of Mo, (d) elemental analysis diagram of Co, (e) elemental analysis diagram of Al, (f) elemental analysis diagram of Ti. Detailed Description of the Invention

[0019] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0020] The metal ceramic material of the present invention is a metal ceramic material toughened by in-situ self-generated NiMoCoAlTi high-entropy alloy. The in-situ self-generated NiMoCoAlTi high-entropy alloy toughened metal ceramic material uses Ti(C,N) as the matrix, adds micron Ni, Mo, Co, Al, and Ti as reinforcing phases, and is sintered by spark plasma coupling high-frequency induction. The mass percentage content of each component is: Ti(C,N) 80 - 95%, Ni 1 - 4%, Mo 1 - 4%, Co 1 - 4%, Al 1 - 4%, Ti 1 - 4%.

[0021] The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened metal ceramic material of the present invention has the raw material component ratio as described above and includes the following steps:

[0022] (1) Add polyethylene glycol into absolute ethanol, stir with constant temperature in a water bath, and cool to room temperature to obtain a polyethylene glycol - absolute ethanol dispersion;

[0023] (2) Mix Ti(C,N) powder, Ni powder, Mo powder, Co powder, Al powder, and Ti powder according to the mass ratio, add them to the prepared polyethylene glycol - absolute ethanol dispersion liquid, and perform ultrasonic dispersion and stirring to obtain a mixed solution;

[0024] (3) Pour the prepared mixed solution and grinding balls into a can. The weight ratio of the total amount of raw materials to the grinding balls is 1:10, and ball mill for 70 - 94 h under a protective atmosphere;

[0025] (4) Vacuum - dry and screen the ball - milled slurry to obtain a high - entropy alloy toughened titanium carbonitride cermet mixed powder, and seal it for standby;

[0026] (5) Place the prepared high - entropy alloy toughened titanium carbonitride cermet mixed powder in a graphite mold, and perform spark plasma coupled with high - frequency induction sintering under a vacuum atmosphere to obtain a high - entropy alloy reinforced titanium carbonitride cermet material.

[0027] Preferably, the average particle size of the Ti(C,N) powder is 1 - 3 μm, and more preferably, it is 1 - 1.5 μm.

[0028] Preferably, the average particle sizes of the Ni powder, Mo powder, Co powder, Al powder, and Ti powder are all 1 - 3 μm, and more preferably, they are 1 - 1.5 μm.

[0029] Preferably, the molecular weight of the polyethylene glycol is 6000 (PEG6000).

[0030] Preferably, in the polyethylene glycol - absolute ethanol dispersion liquid in step (1), the dispersion amount of polyethylene glycol is 2 - 4 g / L.

[0031] Preferably, the mass of polyethylene glycol in the polyethylene glycol - absolute ethanol dispersion liquid in step (2) is 0.09% - 1.1% of the total mass of the Ti(C,N) powder, Ni powder, Mo powder, Co powder, Al powder, and Ti powder.

[0032] Preferably, the temperature of the water - bath constant temperature in step (1) is 55 - 65 °C, magnetic stirring is used for stirring, and the stirring time is 10 - 15 min; the ultrasonic dispersion time in step (2) is 30 - 45 min, and mechanical stirring is used for stirring.

[0033] Preferably, the grinding balls used for ball - milling in step (3) are cemented carbide grinding balls. The cemented carbide balls are a mixture of 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 to those with a diameter of 10 mm is (1 - 2):(1 - 5), and the ball - to - material mass ratio is (10 - 20):1.

[0034] Preferably, the ball milling in the present invention is a high-energy ball milling process, using a stirred high-energy ball mill. The ball milling is carried out under the protection of an inert atmosphere and cooled by circulating water, with a rotation speed of 300 rpm - 500 rpm. Preferably, the protective atmosphere is nitrogen or argon.

[0035] Preferably, in step (4), the drying is vacuum drying. The vacuum drying temperature is 100 - 120 °C, and the vacuum drying time is 24 - 48 h. Preferably, it is 36 h.

[0036] Preferably, the sieve mesh in step (4) is 100 - 200 meshes. Preferably, it is 100 meshes.

[0037] The conditions for spark plasma coupled with high-frequency induction sintering in step (5) are: sintering temperature 1350 - 1500 °C, sintering pressure 30 - 40 MPa, and heat preservation time 10 min - 20 min.

[0038] Preferably, the heating curve is: preheat to 570 °C and raise the temperature to 600 °C within 1 min; raise the temperature to 900 °C at a rate of 100 °C / min; raise the temperature to 1250 °C at a rate of 75 °C / min; raise the temperature to the target temperature at a rate of 50 °C / min.

[0039] The following combines specific embodiments to further elaborate on the present invention. It should be noted that the specific embodiments are interpretations rather than limitations of the present invention.

[0040] In the following embodiments, regarding the mechanical properties of the sintered specimens. First, the sintered block is made into a standard specimen of 3 mm × 4 mm × 25 mm. The flexural strength of the specimen is tested by a universal material testing machine (INSTRON - 5569, Shimadzu Corporation, Jiangsu, China) using the three-point bending method. Among them, the support span is 20 mm, and the loading rate is 0.5 mm / min. The calculation formula is:

[0041] (1);

[0042] In the formula, σ f is the flexural strength (MPa); P is the load (N) at the fracture of the sample; L is the support span (mm); b is the width (mm) of the specimen; h is the height (mm) of the specimen.

[0043] The Vickers hardness of the specimen is tested using a hardness tester (HVS - 50, Shanghai Taiming Optical Instrument Co., Ltd., China), where the load is 196 N and the loading time is 15 s. Five different positions are tested, and the average value is taken as the final Vickers hardness. The calculation formula is:

[0044] (2);

[0045] In the formula, P is the load (196 N), 2a is the arithmetic mean of the indentation diagonals (μm).

[0046] After that, the lengths of the indentation and cracks are measured by the optical microscope equipped with the hardness tester. And the fracture toughness is calculated by the following formula:

[0047] (3);

[0048] In the formula, Н V is the Vickers hardness of the specimen (GPa), a is half of the indentation diagonal length (mm), c is half of the length of the extended crack of the indentation diagonal (mm).

[0049] The ball milling equipment is a planetary high-energy ball mill.

[0050] Example 1

[0051] In the example, the average particle size of Ti(C,N) powder is 1 - 3 μm, and the average particle sizes of Ni, Mo, Co, Al, and Ti powders are 1 - 3 μm, all of which are commercially available products. The polyethylene glycol is PEG6000.

[0052] The mass percentage contents of the components in the high-entropy alloy toughened cermet material are: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%.

[0053] The preparation method of the high-entropy alloy toughened cermet material: includes the following steps:

[0054] (1) Take anhydrous ethanol and place it in a beaker, weigh and add polyethylene glycol, put the beaker in a water bath, magnetically stir at a constant temperature of 55°C 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 2 g / L;

[0055] (2) Mix the powders according to the mass percentage contents of the components: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%, and add them to the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonically disperse for 30 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 total mass of Ti(C,N), Ni, Mo, Co, Al, and Ti powders;

[0056] (3) Place the prepared mixed solution in a ball milling tank. The grinding balls used in ball milling are cemented carbide balls, and the cemented carbide balls are a mixture of cemented carbide balls with diameters of 5 mm and 10 mm. The mass ratio of the 5-mm-diameter and 10-mm-diameter cemented carbide balls is 1:1, and the ball-to-material mass ratio is 20:1. High-energy ball milling is carried out for 84 h under a nitrogen protection atmosphere;

[0057] (4) Vacuum-dry the ball-milled slurry at 120 °C for 24 h, and pass it through a 200-mesh sieve to obtain a high-entropy alloy toughened titanium carbonitride cermet mixed powder;

[0058] (5) Place the high-entropy alloy toughened titanium carbonitride cermet mixed powder in a graphite mold, and carry out spark plasma coupled with high-frequency induction sintering in a vacuum atmosphere. The sintering temperature is 1350 °C, the sintering pressure is 30 MPa, and the heating rate is: preheat to 570 °C and raise the temperature to 600 °C within 1 min; raise the temperature to 900 °C at a rate of 100 °C / min; raise the temperature to 1250 °C at a rate of 75 °C / min; raise the temperature to the target temperature at a rate of 50 °C / min. The holding time is 10 min to obtain a high-entropy alloy toughened cermet material. Cut and process the prepared ceramic material specimen, and measure its mechanical property parameters as follows: flexural strength 1033 MPa, fracture toughness 9.5 MPa∙m 1 / 2 and Vickers hardness 13.43 GPa.

[0059] Example 2

[0060] The mass percentage content of each component in the high-entropy alloy toughened cermet material is: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%.

[0061] The preparation method of the high-entropy alloy toughened cermet material: includes the following steps:

[0062] (1) Take anhydrous ethanol and place it in a beaker. Weigh and add polyethylene glycol. Place the beaker in a water bath and carry out constant-temperature magnetic stirring at 55 °C for 10 min until the polyethylene glycol is completely dissolved. Cool to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion, and the dispersion amount is 2 g / L;

[0063] (2) Mix the powders according to the mass percentage content of each component: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%, and add them to the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1). Carry out ultrasonic dispersion for 30 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 Ti(C,N), Ni, Mo, Co, Al, and Ti powders;

[0064] (3) Place the prepared mixed solution in a ball milling tank. The grinding balls used for ball milling are cemented carbide balls. The cemented carbide balls are a mixture of cemented carbide balls with diameters of 5 mm and 10 mm. The mass ratio of the 5-mm-diameter and 10-mm-diameter cemented carbide balls is 1:1, and the ball-to-material mass ratio is 20:1. High-energy ball milling is carried out for 84 h under a nitrogen protection atmosphere;

[0065] (4) Vacuum-dry the ball-milled slurry at 120 °C for 24 h, and pass it through a 200-mesh sieve to obtain a high-entropy alloy toughened titanium carbonitride cermet mixed powder;

[0066] (5) Place the high-entropy alloy toughened titanium carbonitride cermet mixed powder in a graphite mold, and carry out spark plasma coupled with high-frequency induction sintering under a vacuum atmosphere. The sintering temperature is 1400 °C, the sintering pressure is 30 MPa, and the heating rate is as follows: preheat to 570 °C and raise the temperature to 600 °C within 1 min; raise the temperature to 900 °C at a rate of 100 °C / min; raise the temperature to 1250 °C at a rate of 75 °C / min; raise the temperature to the target temperature at a rate of 50 °C / min. The holding time is 10 min to obtain a high-entropy alloy toughened cermet material. Cut and process the prepared ceramic material sample, and measure its mechanical property parameters as follows: flexural strength of 1153 MPa, fracture toughness of 10.3 MPa∙m 1 / 2 and Vickers hardness of 13.76 GPa.

[0067] Example 3

[0068] The mass percentage content of each component in the high-entropy alloy toughened cermet material is as follows: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%.

[0069] The preparation method of the high-entropy alloy toughened cermet material: includes the following steps:

[0070] (1) Take anhydrous ethanol and place it in a beaker. Weigh and add polyethylene glycol. Place the beaker in a water bath and carry out constant-temperature magnetic stirring at 55 °C for 10 min until the polyethylene glycol is completely dissolved. Cool to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion, and the dispersion amount is 2 g / L;

[0071] (2) Mix the powders according to the mass percentage content of each component: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%, and add them to the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1). Carry out ultrasonic dispersion for 30 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 Ti(C,N), Ni, Mo, Co, Al, and Ti powders;

[0072] (3) Place the prepared mixed solution in a ball milling tank. The grinding balls used for ball milling are cemented carbide grinding balls. The cemented carbide balls are a mixture of 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 to those with a diameter of 10 mm is 1:1, and the ball-to-material mass ratio is 20:1. High-energy ball milling is carried out for 84 h under a nitrogen protection atmosphere;

[0073] (4) Vacuum-dry the ball-milled slurry at a constant temperature of 120 °C for 24 h, and pass it through a 200-mesh sieve to obtain a high-entropy alloy toughened titanium carbonitride cermet mixed powder;

[0074] (5) Place the high-entropy alloy toughened titanium carbonitride cermet mixed powder in a graphite mold, and carry out spark plasma coupling high-frequency induction sintering under a vacuum atmosphere. The sintering temperature is 1450 °C, the sintering pressure is 30 MPa, and the heating rate is as follows: preheat to 570 °C and raise the temperature to 600 °C within 1 min; raise the temperature to 900 °C at a rate of 100 °C / min; raise the temperature to 1250 °C at a rate of 75 °C / min; raise the temperature to the target temperature at a rate of 50 °C / min. The holding time is 10 min to obtain a high-entropy alloy toughened cermet material. Cut and process the prepared ceramic material sample, and measure its mechanical property parameters as follows: flexural strength 1503 MPa, fracture toughness 11.5 MPa∙m 1 / 2 and Vickers hardness 15.12 GPa.

[0075] The electron microscope and element analysis diagrams of the high-entropy alloy toughened cermet material prepared in Example 3 are as Figure 1 shown. It can be clearly seen from Figure 1 that the high-entropy alloy exists at the grain boundaries (i.e., the interfaces between grains), forming an intergranular mixed structure.

[0076] Example 4

[0077] The mass percentage contents of the components in the high-entropy alloy toughened cermet material are as follows: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%.

[0078] The preparation method of the high-entropy alloy toughened cermet material: includes the following steps:

[0079] (1) Take anhydrous ethanol and place it in a beaker. Weigh and add polyethylene glycol. Place the beaker in a water bath and carry out constant-temperature magnetic stirring at 55 °C for 10 min until the polyethylene glycol is completely dissolved. Cool to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion, and the dispersion amount is 2 g / L;

[0080] (2) Mix the powders according to the mass percentage of each component as follows: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%. Add them to the polyethylene glycol - absolute ethanol dispersion prepared in step (1), and perform ultrasonic dispersion for 30 min and mechanical stirring to obtain a mixed solution. The mass of polyethylene glycol in the polyethylene glycol - absolute ethanol dispersion is 0.09% of the total mass of Ti(C,N), Ni, Mo, Co, Al, and Ti powders.

[0081] (3) Place the obtained mixed solution in a ball - milling tank. The grinding balls used for ball - milling are cemented carbide balls. The cemented carbide balls are a mixture of 5 - mm - diameter and 10 - mm - diameter cemented carbide balls, and the mass ratio of 5 - mm - diameter and 10 - mm - diameter cemented carbide balls is 1:1. The ball - to - material mass ratio is 20:1. Perform high - energy ball - milling for 84 h under a nitrogen - protection atmosphere.

[0082] (4) Vacuum - dry the ball - milled slurry at 120 °C for 24 h, and pass it through a 200 - mesh sieve to obtain a high - entropy alloy - toughened titanium carbonitride cermet mixed powder.

[0083] (5) Place the high - entropy alloy - toughened titanium carbonitride cermet mixed powder in a graphite mold, and perform spark plasma coupled with high - frequency induction sintering in a vacuum atmosphere. The sintering temperature is 1500 °C, the sintering pressure is 30 MPa, and the heating rate is as follows: pre - heat to 570 °C and raise the temperature to 600 °C within 1 min; raise the temperature to 900 °C at a rate of 100 °C / min; raise the temperature to 1250 °C at a rate of 75 °C / min; raise the temperature to the target temperature at a rate of 50 °C / min. The holding time is 10 min to obtain a high - entropy alloy - toughened cermet material. Cut and process the obtained ceramic material specimen, and measure its mechanical property parameters as follows: flexural strength 992 MPa, fracture toughness 9.4 MPa∙m 1 / 2 and Vickers hardness 15.66 GPa.

[0084] Example 5

[0085] The mass percentage of each component in the high - entropy alloy - toughened cermet material is: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%.

[0086] The preparation method of the high - entropy alloy - toughened cermet material includes the following steps:

[0087] (1) Take absolute ethanol and place it in a beaker. Weigh and add polyethylene glycol. Place the beaker in a water - bath pot and perform constant - temperature magnetic stirring at 55 °C for 10 min until the polyethylene glycol is completely dissolved. Cool to room temperature to obtain a polyethylene glycol - absolute ethanol dispersion with a dispersion amount of 2 g / L.

[0088] (2) Mix the powders according to the mass percentage of each component as follows: Ti(C,N) - 90%, Ni - 2%, Mo - 2%, Co - 2%, Al - 2%, Ti - 2%. Add them to the polyethylene glycol - absolute ethanol dispersion prepared in step (1), and perform ultrasonic dispersion for 30 min and mechanical stirring to obtain a mixed solution. The mass of polyethylene glycol in the polyethylene glycol - absolute ethanol dispersion is 0.09% of the total mass of Ti(C,N), Ni, Mo, Co, Al, and Ti powders.

[0089] (3) Place the obtained mixed solution in a ball - milling tank. The grinding balls used for ball - milling are cemented carbide balls. The cemented carbide balls are a mixture of 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 to those with a diameter of 10 mm is 1:1, and the ball - to - material mass ratio is 20:1. Perform high - energy ball - milling for 84 h under a nitrogen - protection atmosphere.

[0090] (4) Vacuum - dry the ball - milled slurry at 120 °C for 24 h, and pass it through a 200 - mesh sieve to obtain a high - entropy alloy toughened titanium carbonitride cermet mixed powder.

[0091] (5) Place the high - entropy alloy toughened titanium carbonitride cermet mixed powder in a graphite mold, and perform spark plasma coupled with high - frequency induction sintering in a vacuum atmosphere. The sintering temperature is 1450 °C, the sintering pressure is 35 MPa, and the heating rate is as follows: pre - heat to 570 °C and raise the temperature to 600 °C within 1 min; raise the temperature to 900 °C at a rate of 100 °C / min; raise the temperature to 1250 °C at a rate of 75 °C / min; raise the temperature to the target temperature at a rate of 50 °C / min. The holding time is 10 min to obtain a high - entropy alloy toughened cermet material. Cut and process the obtained ceramic material specimen, and measure its mechanical property parameters as follows: flexural strength 1396 MPa, fracture toughness 10.3 MPa∙m 1 / 2 and Vickers hardness 15.13 GPa.

[0092] Example 6

[0093] The difference between this example and Example 3 is that the sintering pressure in step (5) is set to 40 MPa, and other preparations are the same as in Example 3. Cut and process the obtained ceramic material specimen, and measure its mechanical property parameters as follows: flexural strength 1004 MPa, fracture toughness 9.9 MPa∙m 1 / 2 and Vickers hardness 14.88 GPa.

[0094] Example 7

[0095] The difference between this example and Example 3 is as follows: In step (2), the mass percentages are: Ti(C,N) - 95%, Ni - 1%, Mo - 1%, Co - 1%, Al - 1%, Ti - 1%, and the other preparations are the same as in Example 3. The obtained ceramic material specimen is cut and processed, and its mechanical property parameters are measured as: flexural strength 957 MPa, fracture toughness 9.48 MPa∙m 1 / 2 , Vickers hardness 15.47 GPa.

[0096] Example 8

[0097] The difference between this example and Example 3 is as follows: In step (2), the mass percentages are: Ti(C,N) - 85%, Ni - 3%, Mo - 3%, Co - 3%, Al - 3%, Ti - 3%, and the other preparations are the same as in Example 3. The obtained ceramic material specimen is cut and processed, and its mechanical property parameters are measured as: flexural strength 1305 MPa, fracture toughness 10.27 MPa∙m 1 / 2 , Vickers hardness 13.65 GPa.

[0098] Example 9

[0099] The difference between this example and Example 3 is as follows: In step (2), the mass percentages are: Ti(C,N) - 80%, Ni - 4%, Mo - 4%, Co - 4%, Al - 4%, Ti - 4%, and the other preparations are the same as in Example 3. The obtained ceramic material specimen is cut and processed, and its mechanical property parameters are measured as: flexural strength 1378 MPa, fracture toughness 10.36 MPa∙m 1 / 2 , Vickers hardness 13.55 GPa.

[0100] Comparative Example 1

[0101] The difference between this comparative example and Example 3 is as follows: In step (5), the sintering temperature is set to 1300 °C, and the other preparations are the same as in Example 3. The obtained ceramic material specimen is cut and processed, and its mechanical property parameters are measured as: flexural strength 864 MPa, fracture toughness 6.7 MPa∙m 1 / 2 , Vickers hardness 10.2 GPa.

[0102] Comparative Example 2

[0103] The difference between this comparative example and Example 3 is as follows: Equal masses of Ni, Mo, Co, Al, and Ti are placed in a drum mill and ball-milled under a nitrogen atmosphere protection condition. After the ball-milling is completed, the NiMoCoAlTi high-entropy alloy toughened titanium carbonitride cermet hybrid powder is obtained. Among them, the ball-to-material ratio of the ball-milling is 10:1, the ball-milling speed is 300 rpm, and the ball-milling time is 84 hours. Other preparations are the same as those in Example 3. The prepared ceramic material sample is cut and processed, and the measured mechanical property parameters are: flexural strength 1308 MPa, fracture toughness 8.6 MPa∙m 1 / 2 , Vickers hardness 13.1 GPa.

[0104] Comparative Example 3

[0105] The difference between this comparative example and Example 3 is as follows: In step (2), according to the mass percentage content of each component: Ti(C,N) - 90%, NiMoCoAlTi high-entropy alloy powder - 10% are mixed and added to the polyethylene glycol-anhydrous ethanol dispersion liquid prepared in step (1). Other preparations are the same as those in Example 3. The prepared ceramic material sample is cut and processed, and the measured mechanical property parameters are: flexural strength 1047 MPa, fracture toughness 8.4 MPa∙m 1 / 2 , Vickers hardness 13.74 GPa.

[0106] It can be seen from the comparison between Example 3 and Examples 1-6 and Comparative Example 1 that the sintering temperature and pressure will affect the mechanical properties of the ceramic material.

[0107] It can be seen from the comparison between Example 3 and Examples 7-9 that the ratio of the ceramic material to the metal element will affect the mechanical properties of the ceramic material.

[0108] It can be seen from the comparison between Example 3 and Comparative Example 2 that compared with drum ball-milling, the ceramic material prepared by planetary high-energy ball-milling has better mechanical properties.

[0109] It can be seen from the comparison between Example 3 and Comparative Example 3 that compared with directly adding NiMoCoAlTi high-entropy alloy powder, the ceramic material prepared by the method of directly forming a high-entropy alloy by planetary high-energy ball-milling in the present invention has better mechanical properties.

[0110] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of an in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material, characterized in that, Including: Mix Ti(C,N) powder uniformly with Ni powder, Mo powder, Co powder, Al powder, and Ti powder, disperse them into a polyethylene glycol - absolute ethanol dispersion liquid, perform wet ball milling, dry, and screen to obtain a high - entropy alloy toughened titanium carbonitride cermet mixed powder; Perform spark plasma coupled high - frequency induction sintering on the high - entropy alloy toughened titanium carbonitride cermet mixed powder under vacuum conditions to obtain the product; The in - situ self - generated NiMoCoAlTi high - entropy alloy toughened cermet material consists of the following components by mass percentage: Ti(C,N) 80 - 95%, Ni 1 - 4%, Mo 1 - 4%, Co 1 - 4%, Al 1 - 4%, Ti 1 - 4%, and the sum of the percentages of each component is 100%; The sintering temperature is 1350°C - 1500°C, the sintering pressure is 30MPa - 40MPa, and the heat - preservation time is 10min - 20min; The heating curve is: pre - heat to 570°C and raise the temperature to 600°C within 1min; raise the temperature to 900°C at a rate of 100°C / min; raise the temperature to 1250°C at a rate of 75°C / min; raise the temperature to the target temperature at a rate of 50°C / min.

2. The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material according to claim 1, characterized in that, The average particle size of the Ti(C,N) powder is 1 - 3μm.

3. The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material according to claim 1, characterized in that, The average particle sizes of the Ni powder, Mo powder, Co powder, Al powder, and Ti powder are all 1 - 3μm.

4. The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material according to claim 1, characterized in that, In the polyethylene glycol - absolute ethanol dispersion liquid, the dispersion amount of polyethylene glycol is 2 - 4g / L.

5. The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material as described in claim 1, characterized in that, In the polyethylene glycol - absolute ethanol dispersion liquid, the mass of polyethylene glycol is 0.09% - 1.1% of the total mass of Ti(C,N) powder, Ni powder, Mo powder, Co powder, Al powder, and Ti powder.

6. The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material as described in claim 1, wherein, For the wet ball milling, cemented carbide grinding balls with diameters of 5mm and 10mm are used, the mass ratio of the cemented carbide balls with diameters of 5mm and 10mm is (1 - 2):(1 - 5), and the ball - to - material mass ratio is (10 - 20):

1.

7. The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material according to claim 1, characterized in that, The wet ball milling is carried out under an inert gas protection, the ball - milling time is 70h - 94h, the rotation speed is 300rpm - 500rpm, and circulating water cooling is used.

8. The preparation method of the in-situ self-generated NiMoCoAlTi high-entropy alloy toughened cermet material according to claim 1, characterized in that, The mesh number of the sieve is 100 - 200 meshes.

9. The in - situ self - generated NiMoCoAlTi high - entropy alloy toughened cermet material prepared by the method according to any one of claims 1 - 8.

Images