阅读说明：本技术 一种岛状结构硬化高韧性碳氮化钛基金属陶瓷及其制备方法 (Island-shaped structure hardened high-toughness titanium carbonitride base metal ceramic and preparation method thereof ) 是由 康希越 贺跃辉 吝楠 张鹛媚 于 2019-08-09 设计创作，主要内容包括：本发明公开了一种岛状结构硬化高韧性碳氮化钛基金属陶瓷及其制备方法,所述氮化钛基金属陶瓷由低粘结相金属陶瓷颗粒与高粘结相金属陶瓷颗粒两种组份烧结制成,两种组份的质量百分比为：低粘结相金属陶瓷颗粒：10～50％,高粘结相金属陶瓷颗粒：50～90％。本发明所提供方案中,以低粘结相金属陶瓷颗粒作为硬化相,通过烧结,形成岛状结构分散于高韧性的金属陶瓷基体中硬化金属陶瓷基体,同时由于两种金属陶瓷颗粒均含有粘结相,但是存在高低浓度差,在烧结过程中,粘结相从高粘结相区域向低粘结相区域扩散,在硬化基体的同时保持着良好的界面关系,从而在达到硬化目的的同时保持较高的韧性。(The invention discloses an island-shaped structure hardened high-toughness titanium carbonitride-based cermet and a preparation method thereof, wherein the titanium nitride-based cermet is prepared by sintering two components, namely low-bonding-phase cermet particles and high-bonding-phase cermet particles, and the two components comprise the following components in percentage by mass: low binder phase cermet particles: 10-50%, high-binder phase cermet particles: 50-90%. In the scheme provided by the invention, the low-binder phase metal ceramic particles are used as a hardening phase, an island structure is formed by sintering and dispersed in a high-toughness metal ceramic matrix to harden the metal ceramic matrix, and simultaneously, because both the metal ceramic particles contain the binder phase and have high and low concentration difference, the binder phase diffuses from a high-binder phase region to a low-binder phase region in the sintering process, and a good interface relation is kept while the matrix is hardened, so that the high toughness is kept while the hardening purpose is achieved.)

1. A island-shaped structure hardened high-toughness titanium carbonitride based cermet is characterized in that: the titanium nitride-based metal ceramic is prepared by sintering two components, namely low-bonding-phase metal ceramic particles and high-bonding-phase metal ceramic particles, wherein the two components comprise the following components in percentage by mass: low binder phase cermet particles: 10-50%, high-binder phase cermet particles: 50-90%; in the low-bonding-phase metal ceramic particles, the mass fraction of a bonding phase A is 5-14%; in the high-bonding-phase metal ceramic particles, the mass fraction of the bonding phase B is 15-25%.

2. The island-structure hardened high toughness titanium carbonitride based cermet according to claim 1 characterized by: the particle size of the low-bonding-phase metal ceramic particles is 30-200 mu m, and the particle size of the high-bonding-phase metal ceramic particles is 60-300 mu m.

3. The island-structure hardened high toughness titanium carbonitride based cermet according to claim 1 characterized by: the low-bonding-phase metal ceramic particles are prepared from the following raw materials in percentage by weight: binding phase A: 5-14%, titanium carbonitride: 45-65% of a carbide additive C: 15-45%, wherein the binder phase A consists of cobalt and nickel, and the carbide additive C consists of tungsten carbide, molybdenum carbide and tantalum carbide.

4. The island-structure hardened high toughness titanium carbonitride based cermet according to claim 3 characterized by: in the raw materials of the low-bonding-phase metal ceramic particles, the particle size of a bonding phase A is 1-3 mu m, the particle size of titanium carbonitride is 2-4 mu m, and the particle size of a carbide additive C is 2-5 mu m; in the binding phase A, the mass ratio of cobalt to nickel is 0.5-1: 1; and in the carbide additive C, the mass ratio is as follows: tungsten carbide, molybdenum carbide and tantalum carbide are 10-20: 5-10: 2-5.

5. The island-structure hardened high toughness titanium carbonitride based cermet according to claim 1 characterized by: the high-bonding-phase metal ceramic particles are prepared from the following raw materials in percentage by weight: and (3) a binding phase B: 15-25%, titanium carbonitride: 35-60%, carbide additive D: 15-45%, wherein the binder phase B consists of cobalt and nickel, and the carbide additive D consists of tungsten carbide, molybdenum carbide and tantalum carbide.

6. The island-structure hardened high toughness titanium carbonitride based cermet according to claim 5 characterized by: in the raw materials of the high-bonding-phase metal ceramic particles, the particle size of a bonding phase B is 1-3 mu m, the particle size of titanium carbonitride is 2-4 mu m, and the particle size of a carbide additive D is 2-5 mu m; in the binding phase B, the mass ratio of cobalt to nickel is 0.5-1: 1; in the carbide additive D, the mass ratio is as follows: tungsten carbide, molybdenum carbide and tantalum carbide are 10-20: 5-10: 2-5.

7. A process for producing an island-like structure-hardened high toughness titanium carbonitride-based cermet according to any one of claims 1 to 6 characterized by: the method comprises the following steps:

1) mixing the raw materials of the low-bonding-phase metal ceramic particles and the carbon black L according to a designed proportion to obtain mixed powder M, adding a forming agent p into the mixed powder M, mixing and granulating to obtain the low-bonding-phase metal ceramic particles; mixing the raw materials of the high-bonding-phase metal ceramic particles and the carbon black R according to a designed proportion to obtain mixed powder N, adding a forming agent q into the mixed powder N, mixing, and granulating to obtain the high-bonding-phase metal ceramic particles;

2) uniformly mixing the low-bonding-phase metal ceramic particles and the high-bonding-phase metal ceramic particles according to the designed proportion, pressing and molding, and sintering to obtain the island structure hardened high-toughness titanium carbonitride base metal ceramic.

8. The method for producing an island-like structure-hardened high-toughness titanium carbonitride-based cermet according to claim 7, characterized by comprising: in the step 1), the adding amount of the carbon black L is 0.2-0.6% of the total mass of the raw materials of the low-binder-phase metal ceramic particles, in the step 1), the adding amount of the carbon black R is 0.2-0.6% of the total mass of the raw materials of the high-binder-phase metal ceramic particles, and the raw materials of the low-binder-phase metal ceramic particles and the carbon black L; all the raw materials of the high-bonding-phase metal ceramic particles and the carbon black R are mixed in a wet ball milling mode, and the ball milling technological parameters are as follows: the ball milling medium is alcohol, the milling balls are hard alloy balls, and the ball-to-material ratio is 5-8: 1; the rotating speed of ball milling is 90-130 r/min, and the ball milling time is 36-60 h.

9. The method for producing an island-like structure-hardened high-toughness titanium carbonitride-based cermet according to claim 7, characterized by comprising: in the step 1), the forming agent p is paraffin, and the adding amount of the forming agent p is 3-5% of the mass of the mixed powder M, and in the step 1), the forming agent q is paraffin, and the adding amount of the forming agent q is 3-5% of the mass of the mixed powder N; the particle size of the low-bonding-phase metal ceramic particles is 30-200 mu m, and the particle size of the high-bonding-phase metal ceramic particles is 60-300 mu m.

10. The method for producing an island-like structure-hardened high-toughness titanium carbonitride-based cermet according to claim 7, characterized by comprising: in the step 2), the mixing mode is granulator mixing or V-shaped mixer mixing, and the mixing time is 30-60 min; in the step 2), the pressing mode is mould pressing or isostatic pressing, the pressing pressure is 100 MPa-150 MPa, in the step 2), the sintering mode is vacuum sintering, the vacuum degree is 0.001-1 Pa, the sintering temperature is 1400-1500 ℃, and the sintering time is 1-2 h.

Technical Field

The invention belongs to the technical field of preparation of metal ceramic materials, relates to a high-hardness and high-toughness titanium carbonitride based metal ceramic, and particularly relates to an island-shaped structure hardened high-toughness titanium carbonitride based metal ceramic and a preparation method thereof.

Background

Titanium carbonitride based cermets are a new type of hard materials that are widely used in the fields of cutting tools and wear resistant structural members due to their high strength and hardness, excellent hot hardness, low coefficient of friction, excellent high temperature stability, and excellent wear resistance. In the japanese machining industry, the amount of cermet tools used is more than thirty-five percent of the total amount, and in europe and america, the amount of cermet tools used is also more than twenty percent, and the range of use is also expanded from the first turning tool milling cutter to drill bits and other tools. Compared with the traditional high-speed steel and hard alloy cutter materials, the titanium carbonitride base cermet cutter has more excellent high-temperature hardness and high-temperature chemical stability, and low friction coefficient, has excellent cutter sticking resistance in the cutting process, can keep sharp for a long time, has higher surface smoothness of a processed material, and has more excellent performances in high-speed cutting, milling and finishing.

Titanium carbonitride based cermets are heterogeneous composite materials consisting essentially of a carbide hard phase and a metal binder phase. The carbide hard phase provides high hardness and wear resistance, and the metal binding phase adheres the hard phase to provide good strength and toughness for the material, so that the ratio of the binding phase to the hard phase and the interfacial bonding strength between the two phases have great influence on the performance of the titanium carbonitride base cermet. When the proportion of the binding phase is high, the material has good strength and toughness, and low high-temperature hardness and wear resistance, and can be quickly worn in the using process; when the proportion of the binder phase is low, the material has high hardness and wear resistance, but the low-content binder phase cannot completely wet excessive carbide hard phase, the toughness is reduced, even pores are formed, and the prepared cutter material is very easy to break under the working condition of strong impact and cannot be normally used. Therefore, in the preparation of conventional titanium carbonitride based cermets, it is difficult to obtain both high hardness and toughness in the materials.

With the gradual increase of the modern industrial level, the requirements of the working conditions of high precision and high cutting speed on the processing materials are more and more severe, and all countries in the world always take the research and development of the cermet with both hardness and toughness as the research and development focus in the fields of the cermet and the machining industry.

Disclosure of Invention

Aiming at the problem that the cermet in the prior art cannot obtain high hardness and high toughness at the same time, the invention aims to provide an island-shaped structure hardened high-toughness titanium carbonitride based cermet and a preparation method thereof. The material is dispersed in a high-bonding-phase metal ceramic matrix with high toughness in an island-shaped structure mode through larger low-bonding-phase metal ceramic particles in a certain particle size range, so that the aim of hardening the metal ceramic is fulfilled. The island-shaped structure refers to high-hardness low-binder phase particles with a certain particle size range, the particles are individually and independently dispersed in the matrix, and the high interface bonding strength can be kept while the hard phase is added, so that the high toughness is kept, and finally the titanium carbonitride base metal ceramic product with high hardness and high toughness can be obtained.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention relates to island-shaped structure hardened high-toughness titanium carbonitride-based cermet, which is prepared by sintering two components, namely low-bonding-phase cermet particles and high-bonding-phase cermet particles, wherein the two components comprise the following components in percentage by mass: low binder phase cermet particles: 10-50%, high-binder phase cermet particles: 50-90%; in the low-bonding-phase metal ceramic particles, the mass fraction of a bonding phase A is 5-14%; in the high-bonding-phase metal ceramic particles, the mass fraction of the bonding phase B is 15-25%.

The titanium carbonitride-based cermet provided by the invention is prepared by sintering low-bonding-phase cermet particles and high-bonding-phase cermet particles, large-scale low-bonding-phase cermet particles are used as a hardening phase, an island-shaped structure is formed by sintering and dispersed in a high-toughness cermet matrix to form the hardened cermet matrix, and because the two cermet particles contain the bonding phase but have high and low concentration difference, the bonding phase diffuses from a high-bonding-phase area to a low-bonding-phase area in the sintering process, and a good interface relation is kept while the matrix is hardened, so that the high toughness is kept while the hardening purpose is achieved.

The inventors have found that the high-viscosity cermet must be substantially hardened with the low binder phase cermet particles as the hardening phase (i.e., added in a relatively small amount) in the context of the present invention to ultimately achieve a high-hardness, high-toughness cermet; however, if the high-viscosity phase cermet particles are used as the toughening phase (i.e., the addition amount is relatively small) to toughen the low-viscosity phase cermet, the binder phase is not sufficiently diffused during the sintering process, and the strength and toughness are low, so that a good use effect cannot be obtained.

Meanwhile, the particle size range and the content of the low-binder phase particles have great influence on the performance of the material, and when the low-binder phase particles are too large or too high, high-hardness phase connection can be caused, the low-binder phase particles cannot be uniformly and independently distributed, and the toughness of the material is rapidly reduced; when the low binder phase particles are too small or the content is too low, the particles too small cannot keep the existence of high-hardness particles due to binder phase diffusion in the sintering process, and when the content is too low, the strengthening effect is not obvious.

Preferably, the average particle size of the low-binder phase cermet particles is 30-200 μm.

More preferably, the low binder phase cermet particles have an average particle diameter of 30 to 100 μm.

It can be seen that the low binder phase cermet particles of the present invention are much larger than the reinforcing phase (typically 2-10 μm in size) of the prior art.

Preferably, the average particle size of the high-binder phase cermet particles is 60-300 μm.

More preferably, the mean particle diameter of the high binder phase cermet particles is 100 to 300 μm.

In a preferred scheme, the two components are as follows by mass percent: low binder phase cermet particles: 20-40%, high-binding phase cermet particles: 60-80%.

As a further optimization, the two components are as follows by mass percent: low binder phase cermet particles: 30-40%, high-bonding-phase metal ceramic particles: 60-70%.

In a preferred scheme, the low-bonding-phase metal ceramic particles are prepared from the following raw materials in percentage by weight: binding phase A: 5-14%, titanium carbonitride: 45-65% of a binder phase A and carbide additives C15-45%, wherein the binder phase A is composed of cobalt and nickel, and the carbide additives C are composed of tungsten carbide, molybdenum carbide and tantalum carbide.

Preferably, the low-binder phase metal ceramic particles are prepared from the following raw materials in percentage by weight: binding phase A: 5-12%, titanium carbonitride: 45-65% of carbide additive C15-45%.

More preferably, in the raw material of the low binder phase cermet particles, the particle size of the binder phase A is 1 to 3 μm, the particle size of the titanium carbonitride is 2 to 4 μm, and the particle size of the carbide additive C is 2 to 5 μm.

In a preferred scheme, the high-bonding-phase metal ceramic particles are prepared from the following raw materials in percentage by weight: and (3) a binding phase B: 15-25%, titanium carbonitride: 35-60%, carbide additive D: 15-45%, wherein the binder phase B consists of cobalt and nickel, and the carbide additive D consists of tungsten carbide, molybdenum carbide and tantalum carbide.

Preferably, the high-binding-phase metal ceramic particles are prepared from the following raw materials in percentage by weight: and (3) a binding phase B: 15-20%, titanium carbonitride: 35-60%, carbide additive D: 15-45%.

More preferably, in the raw material of the high binder phase cermet particles, the particle size of the binder phase B is 1 to 3 μm, the particle size of the titanium carbonitride is 2 to 4 μm, and the particle size of the carbide additive D is 2 to 5 μm.

More preferably, in the binder phase a, the mass ratio of cobalt to nickel is 0.5 to 1: 1; preferably 1: 1.

More preferably, in the binder phase B, the mass ratio of cobalt to nickel is 0.5 to 1: 1; preferably 1: 1.

As a further preference, in the carbide additive C, in terms of mass ratio: tungsten carbide, molybdenum carbide and tantalum carbide are 10-20: 5-10: 2-5, preferably 14-20: 7-10: 3-5.

As a further preference, in the carbide additive D, in terms of mass ratio: tungsten carbide, molybdenum carbide and tantalum carbide are 10-20: 5-10: 2-5, preferably 14-20: 7-10: 3-5.

In a preferred embodiment, the titanium carbonitride-based cermet has the following properties: the hardness is 91-93 HRA, the bending strength is 2000-2750 MPa, and the fracture toughness is 9-12 MPa.m^1/2，

The invention discloses a preparation method of island-shaped structure hardened high-toughness titanium carbonitride based cermet, which comprises the following steps of:

1) mixing the raw materials of the low-bonding-phase metal ceramic particles and the carbon black L according to a designed proportion to obtain mixed powder M, adding a forming agent p into the mixed powder M, mixing and granulating to obtain the low-bonding-phase metal ceramic particles; mixing the raw materials of the high-bonding-phase metal ceramic particles and the carbon black R according to a designed proportion to obtain mixed powder N, adding a forming agent q into the mixed powder N, mixing, and granulating to obtain the high-bonding-phase metal ceramic particles;

2) uniformly mixing the low-bonding-phase metal ceramic particles and the high-bonding-phase metal ceramic particles according to the designed proportion, pressing and molding, and sintering to obtain the island structure hardened high-toughness titanium carbonitride base metal ceramic.

Preferably, in the step 1), the adding amount of the carbon black L is 0.2-0.6% of the total mass of the raw materials of the low-binder-phase metal ceramic particles.

Preferably, in the step 1), the adding amount of the carbon black R is 0.2-0.6% of the total mass of the raw materials of the high-binder-phase metal ceramic particles.

In a preferred embodiment, each raw material of the low binder phase cermet particles and carbon black L; all the raw materials of the high-bonding-phase metal ceramic particles and the carbon black R are mixed in a wet ball milling mode, and the ball milling technological parameters are as follows: the ball milling medium is alcohol, the milling balls are hard alloy balls, and the ball-to-material ratio is 5-8: 1; the rotating speed of ball milling is 90-130 r/min, and the ball milling time is 36-60 h.

In the mixing by ball milling, the ball mill to be used is not limited, and for example, a roller ball mill or a planetary ball mill known to those skilled in the art can be used, and since the discharge amount by the roller ball mill is large in the mixing, the roller ball mill is preferably used for ball milling.

Preferably, in the step 1), the forming agent p is paraffin, and the addition amount of the forming agent p is 3-5% of the mass of the mixed powder M.

Preferably, in the step 1), the forming agent q is paraffin, and the addition amount of the forming agent q is 3-5% of the mass of the mixed powder N.

In the present invention, the granulation is spray granulation, roller granulation or sieve granulation.

Preferably, the average particle size of the low-binder phase cermet particles is 30-200 μm.

More preferably, the low binder phase cermet particles have an average particle diameter of 30 to 100 μm.

Preferably, the average particle size of the high-binder phase cermet particles is 60-300 μm.

More preferably, the mean particle diameter of the high binder phase cermet particles is 100 to 300 μm.

Preferably, in the step 2), the mixing mode is granulator mixing, V-shaped mixer or double-cone mixer mixing, and the mixing time is 30-60 min.

Preferably, in the step 2), the pressing mode is die pressing or isostatic pressing, and the pressing pressure is 100MPa to 150 MPa.

More preferably, in the step 2), the pressing mode is isostatic pressing, and the pressing pressure is 120 to 150 MPa.

In a preferable scheme, in the step 2), the sintering mode is vacuum sintering, the vacuum degree is 0.001-1 Pa, the sintering temperature is 1400-1500 ℃, and the sintering time is 1-2 hours.

According to the technical scheme, the high-hardness low-bonding-phase metal ceramic particles are used as a hardening phase and are sintered to form an island-shaped structure, so that the high-toughness high-bonding-phase metal ceramic matrix is hardened. In the prior art, high-hardness carbide is adopted for reinforcement, however, the addition amount of the high-hardness carbide increases the interface of low binding force in the material, and the toughness of the material is reduced sharply. In the invention, the hardening phase is high-hardness low-bonding-phase metal ceramic particles, and the concentration of the bonding phase is different from that of the high-bonding-phase metal ceramic particles, so that the bonding phase is diffused from a high-bonding-phase region to a low-bonding-phase region, a good interface relation is kept while the matrix is hardened, and high toughness is kept while the hardening purpose is achieved.

Compared with the conventional metal ceramic, the technology has the following advantages:

1. a novel metal ceramic hardening idea is provided, the purpose of hardening is achieved through novel high-hardness particles, the island-shaped hardened structure and the substrate have good interface relation and good interface bonding force, and the purpose of hardening is achieved while high toughness is kept.

2. During use, the island-like hardened structures act as a hardened phase increasing the wear resistance of the tool. Meanwhile, in the failure process, compared with the direct falling of the traditional hard carbide, the island-shaped hardened structure is gradually peeled off in the use process, and meanwhile, the island-shaped hardened structure has better retention with a substrate with good toughness, so that the situation of collapse is avoided.

3. The high-binding phase particles as a matrix have high toughness, and in the process of crack propagation, the high-binding phase can absorb more crack propagation energy, effectively block the crack propagation and improve the strength and fracture toughness of the material.

4. The island-shaped structure hardened high-toughness titanium carbonitride based cermet provided by the invention has the advantages of excellent performance, simple preparation process, capability of effectively improving the hardness of the material and simultaneously keeping higher toughness, short technical process, small investment and convenient industrialization.

Drawings

FIG. 1 shows a titanium carbonitride-based cermet prepared by a conventional technique according to comparative example 4.

FIG. 2 shows an island-like structure-hardened titanium carbonitride-based cermet prepared in example 1.

FIG. 3 shows an island-like structure-hardened titanium carbonitride-based cermet prepared in comparative example 3.

Detailed Description