Preparation method of high-entropy cutter for cutting titanium alloy and high-entropy cutter

Abstract

The invention provides a preparation method of a high-entropy cutter for titanium alloy cutting, and belongs to the technical field of metal cermes.The preparation method comprises the steps that a metal ceramic matrix with a high-entropy alloy phase on the surface layer is prepared; carrying out surface activation treatment on the metal ceramic matrix; depositing a high-entropy alloy coating on the surface of the metal ceramic matrix subjected to surface activation treatment; and depositing a high-entropy nitride coating on the surface of the high-entropy alloy coating to obtain the high-entropy cutter. The high-entropy cutter prepared through the method can meet stable cutting of titanium alloy at the cutting temperature of 1000 DEG C and has excellent high-temperature oxidation resistance and high-temperature stability, the service life of the titanium alloy machining cutter is prolonged, and the machining cost of the titanium alloy is reduced. The invention further provides the high-entropy cutter for cutting the titanium alloy.

Description

Technical Field

[0001] The invention belongs to the technical field of metal ceramics, and in particular relates to a preparation method of a high entropy cutting tool for titanium alloy cutting and the high entropy cutting tool. Background Art

[0002] Titanium alloys have many excellent material properties, such as high mechanical properties, corrosion resistance, biosafety, and good reactivity with biological tissues. They are widely used in research and development and production. For example: 1. Aerospace: titanium alloys are used to manufacture mechanical equipment such as aircraft engines and aerodynamic systems, or to make important parts such as engine casings and blades; 2. Biomedical: titanium alloys are used to make or repair artificial implants in the human body, such as artificial bones; 3. Military shipbuilding: titanium alloys are used to make structural parts for engines, tanks, armored vehicles, and large ships; 4. Daily life: titanium alloys are used to make high-strength parts such as bearings and bicycle frames. Although titanium alloys are widely used, their processing and manufacturing is a difficult problem.

[0003] At present, although direct forming methods such as precision forging have been developed to minimize the machining of titanium parts, many titanium alloy parts, such as those used in gas turbine engines and fuselages, are still manufactured through operations such as turning, drilling and milling to keep costs low. However, titanium alloys are also difficult to machine because of their unique material properties: the low thermal conductivity of titanium alloys, the high cutting temperature and high strength generated, lead to severe abrasive wear and diffusion wear of the tool; the low modulus of titanium alloys leads to chatter and high radial cutting forces; the high chemical reactivity of titanium alloys promotes the further progress of diffusion wear. Therefore, the common wear of the tool during titanium alloy machining is mainly the combined effect of mechanical wear, plastic deformation, workpiece material adhesion and diffusion wear between the workpiece and the tool, and the diffusion wear between the tool and the workpiece plays a more critical role at high cutting speeds. When higher cutting speeds are applied to titanium alloys, the relative contribution of tool diffusion wear to the total wear increases exponentially. Therefore, the unique material properties of titanium alloys lead to rapid wear and premature failure of cutting tools used in machining titanium alloys, which seriously affects the machining quality of titanium alloy workpieces and greatly increases the machining cost of titanium alloys. Summary of the invention

[0004] In order to solve the problem of sudden reduction in tool life due to high-temperature failure during the cutting process of titanium alloy machining tools, the present invention provides a method for preparing a high-entropy tool for titanium alloy cutting. The high-entropy tool prepared by the method can meet the stable cutting of titanium alloy at a cutting temperature of 1000°C, has excellent high-temperature oxidation resistance and high-temperature stability, improves the service life of titanium alloy machining tools, and is beneficial to reducing the processing cost of titanium alloys.

[0005] The invention also provides a high entropy tool for cutting titanium alloy.

[0006] The present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for preparing a high entropy cutting tool for titanium alloy cutting, the preparation method comprising:

[0008] preparing a metal-ceramic matrix having a high entropy alloy phase on the surface;

[0009] Performing surface activation treatment on the metal ceramic substrate;

[0010] Depositing a high entropy alloy coating on the surface of the metal ceramic substrate that has been subjected to surface activation treatment;

[0011] A high entropy nitride coating is deposited on the surface of the high entropy alloy coating to obtain a high entropy tool.

[0012] Furthermore, the method of preparing a metal-ceramic matrix having a high entropy alloy phase on the surface specifically comprises:

[0013] Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2, granulating the metal ceramic raw material C2 and filling it into a tool mold for pre-pressing to obtain a preform;

[0014] The high entropy metal raw material C1 is pelletized and filled into the tool mold, and covered on the surface of the preform, and then secondary pre-pressed to obtain a secondary preform;

[0015] performing final pressing on the secondary preform in the tool mold to obtain a matrix blank;

[0016] The matrix blank is vacuum sintered to obtain a metal ceramic matrix with a high entropy alloy phase on the surface.

[0017] Furthermore, the method of preparing a metal-ceramic matrix having a high entropy alloy phase on the surface specifically comprises:

[0018] Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2 in a mass ratio of 1:4, granulating the metal ceramic raw material C2 and filling it into a tool mold, and pre-pressing it under a pressure of 10T to obtain a preform;

[0019] The high entropy metal raw material C1 is granulated and filled into the tool mold, and evenly covers the surface of the preform, and then a secondary pre-pressing is performed under a pressure of 10T to obtain a secondary preform;

[0020] The secondary preform is finally pressed in the tool mold at a pressure of 100T to obtain a matrix blank;

[0021] In a vacuum environment, the matrix blank is sintered by microwave, the sintering heating rate is 15-25°C / min, the holding temperature is 1400-1500°C, and the holding time is 45-90min, so as to obtain a metal ceramic matrix with a high entropy alloy phase on the surface.

[0022] Furthermore, in terms of mass fraction, the composition of the high entropy metal raw material C1 is as follows:

[0023] Ti: 15~52%; Ni: 5.0~15.0%; Co: 5.0~15.0%; Cr: 5.0~15.0%; Nb: 5.0~15.0%; Ta: 5.0~15.0%; Mo: 2.0~16.0%; W: 2.0~15.0%; C: 2.0~7.0%; N: 2.0~3.0%;

[0024] In terms of mass fraction, the composition of the metal ceramic raw material C2 is as follows:

[0025] Ti: 50~62%; Ni: 2.0~3.0%; Co: 2.0~3.0%; Cr: 2.0~3.0%; Nb: 2.0~3.0%; Ta: 2.0~3.0%; Mo: 11.0~16.0%; W: 7.0~15.0%; C: 7.0~11.0%; N: 2~3%.

[0026] Furthermore, the surface activation treatment of the metal ceramic substrate specifically includes:

[0027] Grinding and polishing the surface of the metal ceramic substrate, and placing it in a NaOH solution for surface treatment after cleaning;

[0028] After the surface treatment is completed, the surface is placed in an acid solution for acid treatment;

[0029] After the acid treatment, the solution is placed in K2Cr2O7 for high activation treatment;

[0030] After the high activation treatment is completed, the surface is cleaned.

[0031] Furthermore, the surface activation treatment of the metal ceramic substrate specifically includes:

[0032] The surface of the metal ceramic substrate is roughly ground and then polished, and after cleaning, placed in a 1-3 mol / L NaOH solution for surface treatment, and the surface treatment lasts for 20-90 seconds;

[0033] After the surface treatment is completed, the surface is placed in an acid solution containing HNO3, HCl and HF for acid treatment, and the duration of the acid treatment is 45 to 100 seconds;

[0034] After the acid treatment, the solution is placed in 0.001-0.01 mol / L K2Cr2O7 solution for high activation treatment, and the duration of the high activation treatment is 1-3 hours;

[0035] After the high activation treatment, alcohol is used to clean the surface;

[0036] Wherein, in the acid solution, the total concentration of HNO3, HCl and HF is 1.2-3.5 mol / L, and the molar concentration ratio of HNO3, HCl and HF is 1:1:2.

[0037] Furthermore, the step of depositing a high entropy alloy coating on the surface of the metal ceramic substrate after surface activation treatment specifically includes:

[0038] In a nitrogen atmosphere, the metal ceramic substrate subjected to surface activation treatment is heated to 350-550° C., and then a high entropy alloy target material A is used to magnetron sputter and deposit a high entropy alloy coating on the surface of the heated metal ceramic substrate;

[0039] Wherein, the composition of the high entropy alloy target material A is as follows, in terms of mass fraction:

[0040] Ni: 15.0~25.0%; Co: 15.0~25.0%; Cr: 15.0~25.0%; Nb: 15.0~25.0%; Ta: 15.0~25.0%; inevitable impurity elements: 0~1%.

[0041] Furthermore, in a nitrogen atmosphere, the metal ceramic substrate subjected to surface activation treatment is heated to 350-550° C., and then a high entropy alloy target A is used to magnetron sputter and deposit a high entropy alloy coating on the surface of the heated metal ceramic substrate, specifically comprising:

[0042] In a nitrogen atmosphere, the metal ceramic substrate subjected to surface activation treatment is heated to 350-550° C., kept at this temperature for 20-60 minutes, and then magnetron sputtered on the surface of the heated metal ceramic substrate using a high entropy alloy target A to deposit a high entropy alloy coating;

[0043] Among them, the deposition process of the high entropy alloy coating is carried out in a high-energy arc pulse magnetron sputtering device, the metal ceramic substrate bias is -20 to -200V, the nitrogen flow rate is 20 to 120sccm, the target current gradually increases from 0A to 70 to 110A, the pulse voltage frequency is 30kHz, the duty cycle is 75%, and the deposition time is 5 to 25min.

[0044] Furthermore, the step of depositing a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool specifically includes:

[0045] Using a high entropy nitride target material to deposit a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool;

[0046] Wherein, in terms of mass fraction, the composition of the high entropy nitride target is as follows:

[0047] Cr: 15.0-25.0%; Nb: 15.0-25.0%; Ta: 15.0-25.0%; X: 15.0-25.0%; Y: 15.0-25.0%; inevitable impurity elements: 0-1%, X and Y are selected from any two of Al, Ti, V and Si.

[0048] Furthermore, the high entropy nitride target is used to deposit a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool, which specifically includes:

[0049] A high entropy nitride target is used to deposit a high entropy nitride coating on the surface of the high entropy alloy coating, and a high entropy tool is obtained after cooling;

[0050] The deposition process of the high entropy nitride coating is carried out in an ion plating device with a pulse voltage frequency of 5 to 80 kHz, a power of 0.1 to 1 kW, a bias voltage of -40 to -60 V, a target current of 30 to 100 A, a duty cycle of 75%, a nitrogen flow rate of 20 to 120 sccm, and a deposition time of 30 to 60 min.

[0051] Based on the same inventive concept, the present invention provides a high entropy tool for cutting titanium alloys, and the high entropy tool is prepared by the above-mentioned preparation method of a high entropy tool for cutting titanium alloys.

[0052] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0053] 1. The present invention discloses a method for preparing a high entropy cutting tool for titanium alloy cutting. The method first prepares a metal ceramic substrate having a high entropy alloy phase on the surface. After surface activation treatment, a high entropy alloy coating and a high entropy nitride coating are deposited layer by layer on the surface of the metal ceramic substrate. The prepared high entropy coating tool has high entropy materials in multiple phases and multiple layers from the substrate to the coating, which gives full play to the high entropy effect of the high entropy material, can significantly improve the high-temperature oxidation resistance and high-temperature stability of the tool, and can meet the stable cutting of titanium alloys at a cutting temperature of 1000°C.

[0054] 2. The present invention discloses a method for preparing a high entropy cutting tool for titanium alloy cutting. When preparing a metal ceramic substrate with a high entropy alloy phase on the surface, the method realizes the high entropy alloy phase distribution from the surface to the core of the metal ceramic substrate from high to low through component design + layer-by-layer pressing + microwave sintering, and the surface is rich in high entropy alloy phase, and chemical reagents are used to perform bond breaking and atom deficiency treatment on the high entropy alloy phase rich in the surface of the metal ceramic substrate, so that in the surface high entropy alloy layer, a large area of ​​metal atomic vacancies appear in the high entropy alloy phase with severe lattice distortion, thereby increasing its ability to capture atoms, and then preferentially depositing high entropy alloy metal as the bottom coating. Since the high entropy alloy metal atom types have at least five types that can be combined with the surface of the metal ceramic substrate, the high entropy alloy metal atom can be easily separated from the surface of the metal ceramic substrate. A large number of metal atoms combine with vacancies and are then captured by the vacancies, thereby achieving strong bonding between the coating and the substrate. To ensure that the interlayer bonding force between the high-entropy nitride coating and the bottom high-entropy alloy coating is high and the coating can grow densely, the high-entropy nitride coating selected by the present invention has at least three elements that are the same as the bottom coating, and the atomic mutual diffusion caused by chemical affinity is increased as much as possible. The surface coating makes full use of the high-temperature resistance of the ceramic. During the cutting process, the surface coating has good high-temperature red hardness and good continuous wear resistance under high-temperature conditions. It effectively solves the bonding wear caused by the phase change of the substrate cobalt phase due to high temperature and the diffusion of elements of the processed workpiece to the tool, thereby increasing the service life of the tool.

[0055] 3. The present invention discloses a method for preparing a high entropy tool for cutting titanium alloys. The high entropy tool prepared by the method has diffusion interlaced layers containing three or more atoms between the substrate and the coating and between the coating and the coating, which can significantly improve the bonding strength between the layers of the high entropy tool. In addition, the surface of the metal ceramic substrate of the present invention is a high entropy alloy-rich layer, and the bottom layer of the coating is a high entropy alloy layer, which can make the transition between the substrate and the coating smooth and improve their bonding strength, reduce the crack initiation caused by the interface effect between the coating and the substrate, and the coating is not easy to peel off, thereby improving the service life of the titanium alloy processing tool and helping to reduce the processing cost of titanium alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0057] Figure 1 This is the interface morphology of the metal ceramic substrate prepared in Example 1.

[0058] Figure 2 This is the flank wear morphology of TC4 titanium alloy cut by the high entropy tool prepared in Example 1 for 95 minutes.

[0059] Figure 3 This is the wear diagram of the flank face of the TC4 titanium alloy tool cut by the high entropy tool prepared in Example 1. DETAILED DESCRIPTION

[0060] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0061] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0062] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0063] The technical principle of the present invention is as follows:

[0064] The present invention provides a method for preparing a high entropy cutting tool for titanium alloy cutting, the preparation method comprising:

[0065] S1. preparing a metal ceramic substrate having a high entropy alloy phase on the surface;

[0066] S2. Surface activation treatment of the metal-ceramic substrate;

[0067] S3. Depositing a high entropy alloy coating on the surface of the metal-ceramic substrate after surface activation treatment;

[0068] S4. Depositing a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool.

[0069] Step S1 specifically includes:

[0070] Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2, granulating the metal ceramic raw material C2 and filling it into a tool mold for pre-pressing to obtain a preform;

[0071] The high entropy metal raw material C1 is pelletized and filled into the tool mold, and covered on the surface of the preform, and then secondary pre-pressed to obtain a secondary preform;

[0072] performing final pressing on the secondary preform in the tool mold to obtain a matrix blank;

[0073] The matrix blank is vacuum sintered to obtain a metal ceramic matrix with a high entropy alloy phase on the surface.

[0074] More specifically, step S1 includes:

[0075] Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2 in a mass ratio of 1:4, granulating the metal ceramic raw material C2 and filling it into a tool mold, and pre-pressing it under a pressure of 10T to obtain a preform;

[0076] The high entropy metal raw material C1 is granulated and filled into the tool mold, and evenly covers the surface of the preform, and then a secondary pre-pressing is performed under a pressure of 10T to obtain a secondary preform;

[0077] The secondary preform is finally pressed in the tool mold at a pressure of 100T to obtain a matrix blank;

[0078] In a vacuum environment, the matrix blank is sintered by microwave, the sintering heating rate is 15-25°C / min, the holding temperature is 1400-1500°C, and the holding time is 45-90min, so as to obtain a metal ceramic matrix with a high entropy alloy phase on the surface.

[0079] Wherein, the composition of the high entropy metal raw material C1 is as follows, in terms of mass fraction:

[0080] Ti: 15~52%; Ni: 5.0~15.0%; Co: 5.0~15.0%; Cr: 5.0~15.0%; Nb: 5.0~15.0%; Ta: 5.0~15.0%; Mo: 2.0~16.0%; W: 2.0~15.0%; C: 2.0~7.0%; N: 2.0~3.0%;

[0081] In terms of mass fraction, the composition of the metal ceramic raw material C2 is as follows:

[0082] Ti: 50~62%; Ni: 2.0~3.0%; Co: 2.0~3.0%; Cr: 2.0~3.0%; Nb: 2.0~3.0%; Ta: 2.0~3.0%; Mo: 11.0~16.0%; W: 7.0~15.0%; C: 7.0~11.0%; N: 2~3%.

[0083] In the present invention, the microwave sintering temperature is 1400-1500° C., which has the advantages of fast volumetric heating of the matrix and good material density. At the same time, microwave sintering accelerates the mass transfer process of the material, thereby obtaining a more delicate grain structure.

[0084] In the present invention, the high entropy metal raw material C1 adopts the above composition and proportion, Ti, W, Ni, Co are consistent with the metal ceramic material elements, the material has good wettability during the sintering process, and pores are prevented from being generated between interfaces. At the same time, the addition of Mo can effectively reduce the wettability of the material and reduce the lattice defects generated during the solid solution crystallization process; the addition of Ta and Nb elements has the effect of increasing the high-temperature creep resistance of the matrix material, and ensures that the matrix has sufficient high-temperature mechanical properties during the instantaneous high-temperature process.

[0085] The metal ceramic raw material C2 adopts the above composition and proportion. The metal ceramic bonding phase Co\Cr is configured according to the mass fraction characteristic of 1:1. At the same time, Mo element is added to ensure that the metal ceramic has strong fracture toughness to prevent brittle fracture of the tool during cutting; its C:N is 7:3. This is a typical titanium carbonitride-based metal ceramic with a core-ring structure, and its matrix has the characteristics of high wear resistance and low friction coefficient; the addition of Nb and Ta has better high-temperature creep resistance for the matrix material, and some elements are solid-dissolved in the bonding phase Co\Cr to enhance the mechanical properties of the bonding phase. At the same time, NbC and TaC have the characteristics of refining the grain structure, making the material grains denser.

[0086] Step S2 specifically includes:

[0087] The surface of the metal ceramic substrate is roughly ground and then polished, and then washed and placed in a NaOH solution for surface treatment;

[0088] After the surface treatment is completed, the surface is placed in an acid solution for acid treatment;

[0089] After the acid treatment, the solution is placed in K2Cr2O7 for high activation treatment;

[0090] After the high activation treatment is completed, the surface is cleaned.

[0091] In the present invention, the purpose of rough grinding and polishing the surface of the metal ceramic substrate is to remove the sintered oxide layer on the surface and expose the nucleation points to facilitate nucleation growth.

[0092] The purpose of alkali treatment, acid treatment and K2Cr2O7 solution treatment of the metal ceramic substrate is to remove surface grease and other oxides and clean the material surface.

[0093] More specifically, step S2 includes:

[0094] The surface of the metal ceramic substrate is ground and polished, and after cleaning, placed in a 1-3 mol / L NaOH solution for surface treatment, and the surface treatment lasts for 20-90 seconds;

[0095] After the surface treatment is completed, the surface is placed in an acid solution containing HNO3, HCl and HF for acid treatment, and the duration of the acid treatment is 45 to 100 seconds;

[0096] After the acid treatment, the solution is placed in a 0.001-0.01 mol / L K2Cr2O7 solution for high activation treatment, and the high activation treatment lasts for 1-3 hours;

[0097] After the high activation treatment, alcohol is used to clean the surface;

[0098] Wherein, in the acid solution, the total concentration of HNO3, HCl and HF is 1.2-3.5 mol / L, and the molar concentration ratio of HNO3, HCl and HF is 1:1:2.

[0099] In the present invention, the acid solution using HNO3, HCl and HF has the advantage of being able to remove surface residues and prevent hydrogenation of the substrate surface.

[0100] In the present invention, the advantage of the K2Cr2O7 solution concentration of 0.001 to 0.01 mol / L is that it can generate more nucleation growth points on the substrate surface and form a single layer of surface texture on the surface. If the concentration is lower than this, the surface texture is not fully formed and the substrate-coating interface bonding performance is poor. If the concentration is higher than this, the surface grains will be excessively corroded to form larger surface pits, resulting in uneven deposition.

[0101] Step S3 specifically includes:

[0102] In a nitrogen atmosphere, the metal ceramic substrate subjected to surface activation treatment is heated to 350-550° C., and then a high entropy alloy target material A is used to magnetron sputter and deposit a high entropy alloy coating on the surface of the heated metal ceramic substrate;

[0103] Wherein, the composition of the high entropy alloy target material A is as follows, in terms of mass fraction:

[0104] Ni: 15.0~25.0%; Co: 15.0~25.0%; Cr: 15.0~25.0%; Nb: 15.0~25.0%; Ta: 15.0~25.0%; inevitable impurity elements: 0~1%.

[0105] In the present invention, the metal ceramic matrix is ​​heated to 350-550° C., which is the optimal binding temperature of metal ions. When metal particles are adsorbed on the surface of the sample, they have the characteristics of low stress and greater density.

[0106] In the present invention, the high entropy alloy target material A adopts the above composition, and the five-element high entropy alloy can react with N +The nitride film with high hardness and high oxidation resistance is effectively combined, and the number of face-centered cubic grains formed during the preparation process increases, which further improves the crystallinity of the grains.

[0107] More specifically, step S3 includes:

[0108] In a nitrogen atmosphere, the metal ceramic substrate subjected to surface activation treatment is heated to 350-550° C., kept at this temperature for 20-60 minutes, and then magnetron sputtered on the surface of the heated metal ceramic substrate using a high entropy alloy target A to deposit a high entropy alloy coating;

[0109] Among them, in the deposition process of the high entropy alloy coating, the bias voltage is -20 to -200 V, the nitrogen flow rate is 20 to 120 sccm, the target current gradually increases from 0 A to 70 to 110 A, the pulse voltage frequency is 30 kHz, the duty cycle is 75%, and the deposition time is 5 to 25 min.

[0110] In the present invention, the deposition of the high entropy alloy coating using the above process parameters has the advantage that the film has a higher density and a smoother surface structure. When the target current is 70-110A and the pulse voltage frequency is 30KHz, the initial velocity of the ions is high, and the bias voltage of -20 to -200V makes the ions finally bombard the substrate at a high speed, making the film denser, while the residual stress is small, the film-base bonding force is large, and the grain growth direction of the coating is consistent.

[0111] Step S4 specifically includes:

[0112] Using a high entropy nitride target material to deposit a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool;

[0113] Wherein, in terms of mass fraction, the composition of the high entropy nitride target is as follows:

[0114] Cr: 15.0-25.0%; Nb: 15.0-25.0%; Ta: 15.0-25.0%; X: 15.0-25.0%; Y: 15.0-25.0%; inevitable impurity elements: 0-1%, X and Y are selected from any two of Al, Ti, V and Si.

[0115] In the present invention, the high entropy nitride target uses nitrides such as Al, Ti, V, and Si (the elements will combine with N+ after being granulated), which can effectively reduce the friction coefficient of the substrate surface. During high-temperature friction, these four nitrides can combine with oxygen to generate wear-resistant ceramic oxides.

[0116] More specifically, step S4 includes:

[0117] A high entropy nitride target is used to deposit a high entropy nitride coating on the surface of the high entropy alloy coating, and a high entropy tool is obtained after cooling;

[0118] Among them, in the deposition process of the high entropy nitride coating, the pulse voltage frequency is 5 to 80 kHz, the power is 0.1 to 1 kW, the bias voltage is -40 to -60 V, the target current is 30 to 100 A, the duty cycle is 75%, the nitrogen flow rate is 20 to 120 sccm, and the deposition time is 30 to 60 min.

[0119] In the present invention, the advantage of using the above-mentioned process parameters for the deposition of the high entropy nitride coating is that during the deposition process, the metal ions can be combined with the N ions on the metal surface to form a high-temperature resistant ceramic oxide layer. At the same time, the speed of the ions to the substrate surface should not be too large, otherwise the ceramic phase will form a brittle face-centered cubic structure without a certain toughness, which will cause large-scale peeling of the coating during use.

[0120] The preparation method of a high entropy cutting tool for titanium alloy cutting and the high entropy cutting tool of the present application will be described in detail below in combination with embodiments and experimental data.

[0121] Example 1

[0122] The present embodiment provides a method for preparing a high entropy cutting tool for titanium alloy cutting, which specifically includes:

[0123] 1. Prepare a metal ceramic matrix with a high entropy alloy phase on the surface.

[0124] (1) Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2, respectively granulating the raw materials C1 and C2, the granulation method is as follows: putting the raw material C1 or C2 powder and the cemented carbide balls into a ball mill at the same time, adding alcohol, and after ball milling for 72 hours, adding the molding agent rubber, passing through an 800 mesh sieve, and granulating (diameter 0.78-1.2 μm).

[0125] (2) After granulating the metal ceramic raw material C2, it is filled into a tool mold, and pre-pressed at a pressure of 10T to obtain a preform; after granulating the high entropy metal raw material C1, it is filled into the tool mold and evenly covers the surface of the preform, and then pre-pressed for a second time at a pressure of 10T to obtain a secondary preform; the secondary preform is finally pressed in the tool mold at a pressure of 100T to obtain a matrix blank. The mass ratio of the high entropy metal raw material C1 to the metal ceramic raw material C2 is 1:4.

[0126] (3) In an environment where the vacuum degree is lower than 0.1 Pa, the matrix blank is rapidly sintered by microwaves, the sintering heating rate is 15°C / min, the holding temperature is 1400°C, and the holding time is 45 min, thereby obtaining a metal ceramic matrix having a high entropy alloy phase on the surface.

[0127] In this embodiment, the composition of the high entropy metal raw material C1 is as follows, in terms of mass fraction:

[0128] Ti: 40%; Ni: 6.0%; Co: 6.0%; Cr: 5.0%; Nb: 5.0%; Ta: 5.0%; Mo: 12.0%; W: 14.0%; C: 5.0%; N: 2%.

[0129] In terms of mass fraction, the composition of the metal ceramic raw material C2 is as follows:

[0130] Ti: 62%; Ni: 2.0%; Co: 2.0%; Cr: 2.0%; Nb: 2.0%; Ta: 2.0%; Mo: 11.0%; W: 7.0%; C: 7.0%; N: 3.0%.

[0131] 2. Surface activation treatment.

[0132] (1) The surface of the metal ceramic substrate is ground and polished step by step until it is smooth, and the polished sample is cleaned by ultrasonic wave.

[0133] (2) The surface of the metal ceramic substrate was treated with a 1 mol / L NaOH solution for 20 seconds; then it was immersed in a HNO3, HCl, and HF solution containing an acid concentration of 1.2 mol / L for acid treatment, wherein the concentration ratio of the three acids HNO3, HCl, and HF was 1:1:2, and the treatment time was 45 seconds; finally, after the surface turned black, it was subjected to a high activation treatment with a 0.001 mol / L K2Cr2O7 solution for 1 hour; the treated metal ceramic substrate was cleaned with alcohol again.

[0134] 3. High entropy alloy coating deposition.

[0135] The sample prepared in step 2 was placed in a coating furnace Huasheng-MA1500, the sample speed was 2r / min, and the furnace was evacuated using a mechanical pump and a molecular pump, and the vacuum degree was less than 3.0×10 -3 Pa, the temperature in the furnace is controlled at 350℃, heated for 20min, and the high entropy alloy target A is turned on to deposit on the metal ceramic substrate, wherein the purity of the high entropy alloy target A is greater than 99%, and its composition is Ni: 20.0wt%; Co: 20.0wt%; Cr: 20.0wt%; Nb: 15.0wt%; Ta: 25.0wt%, the negative bias voltage is set to -110V, and the target current gradually increases from 0A to 90A within 10min, the frequency is 30kHz, the duty cycle is 75%, and the deposition time is 5min.

[0136] 4. High entropy nitride coating deposition.

[0137] The target material is a high entropy nitride target with a purity greater than 99%, and its composition is CrNbTaXY, including Cr: 20.0wt%; Nb: 20.0wt%; Ta: 20.0wt%; V: 25.0wt%; Si: 15.0wt%. The high entropy nitride target is opened on the side wall of the coating furnace, the pulse voltage frequency is 5kHz, the power is 1kW, the bias voltage is -40V, the target current is 60A, the duty cycle is 75%, the nitrogen flow rate is 20sccm, and the deposition time is 60min.

[0138] After the coating process is completed, wait for the temperature in the furnace to drop to room temperature to obtain a high entropy tool.

[0139] The high entropy cutting tool prepared in this embodiment was measured by a Vickers hardness tester with a load of 30 kg, and the measured matrix fracture toughness was 7.6 MPa·m 1 / 2 , hardness is 1638HV 30 The room temperature hardness of the coating measured by a microhardness tester is 34 GPa, the high temperature hardness at 1000°C is 30.2 GPa, and the room temperature bonding strength of the coating measured by a scratch tester is 127 N. In the actual processing process, the tool can stably cut TC4 titanium alloy for 47 minutes at the cutting parameters of cutting speed Vc = 120m / min, cutting feed f = 0.1mm / r, and cutting depth 0.2mm.

[0140] Example 2

[0141] The present embodiment provides a method for preparing a high entropy cutting tool for titanium alloy cutting, which specifically includes:

[0142] 1. Prepare a metal ceramic matrix with a high entropy alloy phase on the surface.

[0143] (1) Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2, respectively granulating the raw materials C1 and C2, the granulation method is as follows: putting the raw material C1 or C2 powder and the cemented carbide balls into a ball mill at the same time, adding alcohol, and after ball milling for 72 hours, adding the molding agent rubber, passing through an 800 mesh sieve, and granulating (0.78-1.2um).

[0144] (2) After granulating the metal ceramic raw material C2, it is filled into a tool mold, and pre-pressed at a pressure of 10T to obtain a preform; after granulating the high entropy metal raw material C1, it is filled into the tool mold and evenly covers the surface of the preform, and then pre-pressed for a second time at a pressure of 10T to obtain a secondary preform; the secondary preform is finally pressed in the tool mold at a pressure of 100T to obtain a matrix blank. The mass ratio of the high entropy metal raw material C1 to the metal ceramic raw material C2 is 1:4.

[0145] (3) In an environment where the vacuum degree is lower than 0.1 Pa, the matrix blank is rapidly sintered by microwaves, the sintering heating rate is 25°C / min, the holding temperature is 1500°C, and the holding time is 90 min, thereby obtaining a metal ceramic matrix with a high entropy alloy phase on the surface.

[0146] In this embodiment, the composition of the high entropy metal raw material C1 is as follows, in terms of mass fraction:

[0147] Ti: 40%; Ni: 6.0%; Co: 6.0%; Cr: 5.0%; Nb: 5.0%; Ta: 5.0%; Mo: 12.0%; W: 14.0%; C: 5.0%; N: 2%. .

[0148] In terms of mass fraction, the composition of the metal ceramic raw material C2 is as follows:

[0149] Ti: 50%; Ni: 3.0%; Co: 3.0%; Cr: 3.0%; Nb: 3.0%; Ta: 3.0%; Mo: 12.0%; W: 12.0%; C: 8.0%; N: 3.0%.

[0150] 2. Surface activation treatment.

[0151] (1) The surface of the metal ceramic substrate is ground and polished step by step until it is smooth, and the polished sample is cleaned by ultrasonic wave.

[0152] (2) The surface of the metal ceramic substrate was treated with a 3 mol / L NaOH solution for 90 seconds; then it was immersed in a HNO3, HCl, and HF solution containing an acid concentration of 3.5 mol / L for acid treatment, wherein the concentration ratio of the three acids HNO3, HCl, and HF was 1:1:2, and the treatment time was 100 seconds; finally, after the surface turned black, it was subjected to a high activation treatment with a 0.01 mol / L K2Cr2O7 solution for 3 hours; the treated metal ceramic substrate was cleaned with alcohol again.

[0153] 3. High entropy alloy coating deposition.

[0154] The sample prepared in step 2 was placed in a coating furnace with a sample speed of 5 r / min. A mechanical pump and a molecular pump were used to evacuate the furnace to a vacuum degree of less than 3.0×10 -3Pa, the temperature in the furnace is controlled at 550℃, heated for 60min, and the high entropy alloy target A is turned on to deposit on the metal ceramic substrate, wherein the purity of the high entropy alloy target A is greater than 99%, and its composition is Ni: 20.0wt%; Co: 20.0wt%; Cr: 20.0wt%; Nb: 20.0wt%; Ta: 20.0wt%, the negative bias voltage is gradually increased from -80V, the target current is 100A, the frequency is 30kHz, the duty cycle is 75%, and the deposition time is 25min.

[0155] 4. High entropy nitride coating deposition.

[0156] The target material is a high entropy nitride target with a purity greater than 99%, and its composition is CrNbTaXY, including Cr: 20.0wt%; Nb: 25.0wt%; Ta: 20.0wt%; V: 20.0wt%; Si: 15.0wt%. The high entropy nitride target is turned on in the coating furnace, the pulse voltage frequency is 80kHz, the power is 1kW, the bias voltage is -60V, the target current is 60A, the duty cycle is 75%, the nitrogen flow rate is 90sccm, and the deposition time is 45min.

[0157] After the coating process is completed, wait for the temperature in the furnace to drop to room temperature to obtain a high entropy tool.

[0158] The metal ceramic coating tool prepared in this example has a matrix fracture toughness of 13.8 MPa·m 1 / 2 , hardness 1423HV 30 The coating has a room temperature hardness of 30.4 GPa, a high temperature hardness of 27.9 GPa at 1000°C, and a coating bonding force of 132 N. It can meet the cutting speed Vc = 70 m / min, cutting feed f = 0.4 mm / r, and cutting depth of 0.6 mm cutting parameters for stable cutting of titanium alloy for 64 minutes.

[0159] Comparative Example 1

[0160] The difference between this comparative example and Example 1 is that the high entropy metal raw material C1 in step (1) and (2) of step 1 is replaced by metal ceramic raw material C2, and the rest of the operations are the same as those in Example 1.

[0161] The tool prepared in this comparative example was measured by a Vickers hardness tester with a load of 30 kg, and the fracture toughness of the matrix was 6.8 MPa·m 1 / 2 , hardness is 1486HV 30The room temperature hardness of the coating measured by a microhardness tester is 32 GPa, the high temperature hardness at 1000°C is 27.63 GPa, and the room temperature bonding force of the coating measured by a scratch tester is 62 N. In the actual processing process, the tool can be cut at a cutting speed of Vc = 120m / min, a cutting feed of f = 0.1mm / r, and a cutting depth of 0.2mm. When the TC4 titanium alloy is processed for 25 minutes, the tool surface coating peels off and the tool substrate is severely adhesively worn.

[0162] Attached Figure 1 The morphology of the interface between the substrate and the coating in Example 1 was observed by SEM at 3000 times.

[0163] Attached Figure 2 This is the surface morphology of the high entropy alloy coated insert in Example 1 when it failed during turning of TC4 titanium alloy. The wear is mainly element diffusion wear and high temperature wear.

[0164] Attached Figure 3 The wear curve of the blade surface during the 95-minute machining of a titanium alloy turning blade is shown in the figure. The flank morphology of the tool was tested every 10 minutes during turning, and finally the wear curve of the turning blade was obtained. The wear measurement of the flank surface was performed using an electron microscope at 10 times magnification. The wear of the blade was stable from 0 to 50 minutes. After more than 50 minutes, the blade wore violently and then gradually failed.

[0165] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0166] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0167] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a high entropy cutting tool for titanium alloy cutting, characterized in that: The preparation method comprises: preparing a metal-ceramic matrix having a high entropy alloy phase on the surface; Performing surface activation treatment on the metal ceramic substrate; Depositing a high entropy alloy coating on the surface of the metal ceramic substrate that has been subjected to surface activation treatment; A high entropy nitride coating is deposited on the surface of the high entropy alloy coating to obtain a high entropy tool.

2. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 1, characterized in that: The method of preparing a metal ceramic substrate having a high entropy alloy phase on the surface comprises: Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2, granulating the metal ceramic raw material C2 and filling it into a tool mold for pre-pressing to obtain a preform; The high entropy metal raw material C1 is pelletized and filled into the tool mold, and covered on the surface of the preform, and then secondary pre-pressed to obtain a secondary preform; performing final pressing on the secondary preform in the tool mold to obtain a matrix blank; The matrix blank is vacuum sintered to obtain a metal ceramic matrix with a high entropy alloy phase on the surface.

3. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 2, characterized in that: The method of preparing a metal ceramic substrate having a high entropy alloy phase on the surface comprises: Weighing a high entropy metal raw material C1 and a metal ceramic raw material C2 in a mass ratio of 1:4, granulating the metal ceramic raw material C2 and filling it into a tool mold, and pre-pressing it under a pressure of 10T to obtain a preform; The high entropy metal raw material C1 is granulated and filled into the tool mold, and evenly covers the surface of the preform, and then a secondary pre-pressing is performed under a pressure of 10T to obtain a secondary preform; The secondary preform is finally pressed in the tool mold at a pressure of 100T to obtain a matrix blank; In a vacuum environment, the matrix blank is sintered by microwave, the sintering heating rate is 15-25°C / min, the holding temperature is 1400-1500°C, and the holding time is 45-90min, so as to obtain a metal ceramic matrix with a high entropy alloy phase on the surface.

4. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 2 or 3, characterized in that: In terms of mass fraction, the composition of the high entropy metal raw material C1 is as follows: Ti: 15~52%; Ni: 5.0~15.0%; Co: 5.0~15.0%; Cr: 5.0~15.0%; Nb: 5.0~15.0%; Ta: 5.0~15.0%; Mo: 2.0~16.0%; W：2.0～15.0％； C：2.0～7.0％； N：2.0～3.0％； In terms of mass fraction, the composition of the metal ceramic raw material C2 is as follows: Ti: 50~62%; Ni: 2.0~3.0%; Co: 2.0~3.0%; Cr: 2.0~3.0%; Nb: 2.0~3.0%; Ta: 2.0~3.0%; Mo: 11.0~16.0%; W：7.0～15.0％； C：7.0～11.0％； N：2～3％。 5. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 1, characterized in that: The surface activation treatment of the metal ceramic substrate specifically includes: The surface of the metal ceramic substrate is roughly ground and then polished, and then washed and placed in a NaOH solution for surface treatment; After the surface treatment is completed, the surface is placed in an acid solution for acid treatment; After the acid treatment, the solution is placed in K2Cr2O7 for high activation treatment; After the high activation treatment is completed, the surface is cleaned.

6. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 5, characterized in that: The surface activation treatment of the metal ceramic substrate specifically includes: The surface of the metal ceramic substrate is ground and polished, and after cleaning, placed in a 1-3 mol / L NaOH solution for surface treatment, and the surface treatment lasts for 20-90 seconds; After the surface treatment is completed, the surface is placed in an acid solution containing HNO3, HCl and HF for acid treatment, and the duration of the acid treatment is 45 to 100 seconds; After the acid treatment, the solution is placed in a 0.001-0.01 mol / L K2Cr2O7 solution for high activation treatment, and the duration of the high activation treatment is 1-3 hours; After the high activation treatment, alcohol is used to clean the surface; Wherein, in the acid solution, the total concentration of HNO3, HCl and HF is 1.2-3.5 mol / L, and the molar concentration ratio of HNO3, HCl and HF is 1:1:

2.

7. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 1, characterized in that: The step of depositing a high entropy alloy coating on the surface of the metal ceramic substrate after surface activation treatment specifically comprises: In a nitrogen atmosphere, the metal ceramic substrate subjected to surface activation treatment is heated to 350-550° C., and then a high entropy alloy target material A is used to magnetron sputter and deposit a high entropy alloy coating on the surface of the heated metal ceramic substrate; Wherein, the composition of the high entropy alloy target material A is as follows, in terms of mass fraction: Ni: 15.0~25.0%; Co: 15.0~25.0%; Cr: 15.0~25.0%; Nb: 15.0~25.0%; Ta: 15.0~25.0%; inevitable impurity elements: 0~1%.

8. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 7, characterized in that: The method comprises: heating the surface activated metal ceramic substrate to 350-550° C. in a nitrogen atmosphere, and then magnetron sputtering the high entropy alloy coating on the surface of the heated metal ceramic substrate using a high entropy alloy target material A. The method comprises: In a nitrogen atmosphere, the metal ceramic substrate subjected to surface activation treatment is heated to 350-550° C., kept at this temperature for 20-60 minutes, and then magnetron sputtered on the surface of the heated metal ceramic substrate using a high entropy alloy target A to deposit a high entropy alloy coating; Among them, the deposition process of the high entropy alloy coating is carried out in a high-energy arc pulse magnetron sputtering device, the metal ceramic substrate bias is -20 to -200V, the nitrogen flow rate is 20 to 120sccm, the target current gradually increases from 0A to 70 to 110A, the pulse voltage frequency is 30kHz, the duty cycle is 75%, and the deposition time is 5 to 25min.

9. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 1, characterized in that: Depositing a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool specifically includes: Using a high entropy nitride target material to deposit a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool; Wherein, in terms of mass fraction, the composition of the high entropy nitride target is as follows: Cr: 15.0-25.0%; Nb: 15.0-25.0%; Ta: 15.0-25.0%; X: 15.0-25.0%; Y: 15.0-25.0%; inevitable impurity elements: 0-1%, X and Y are selected from any two of Al, Ti, V and Si.

10. The method for preparing a high entropy cutting tool for titanium alloy cutting according to claim 9, characterized in that: The method of using a high entropy nitride target to deposit a high entropy nitride coating on the surface of the high entropy alloy coating to obtain a high entropy tool specifically includes: A high entropy nitride target is used to deposit a high entropy nitride coating on the surface of the high entropy alloy coating, and a high entropy tool is obtained after cooling; The deposition process of the high entropy nitride coating is carried out in an ion plating device with a pulse voltage frequency of 5 to 80 kHz, a power of 0.1 to 1 kW, a bias voltage of -40 to -60 V, a target current of 30 to 100 A, a duty cycle of 75%, a nitrogen flow rate of 20 to 120 sccm, and a deposition time of 30 to 60 min.

11. A high entropy cutting tool for titanium alloy cutting, characterized in that: The high entropy cutting tool is prepared by the preparation method of a high entropy cutting tool for titanium alloy cutting according to any one of claims 1 to 10.

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