阅读说明：本技术 一种Ti（C,N）基硬质合金材料及其制备方法 (Ti (C, N) -based hard alloy material and preparation method thereof ) 是由 邱瑜铭 邹芹 于 2019-11-01 设计创作，主要内容包括：本发明涉及一种Ti(C,N)基硬质合金材料及其制备方法,属于硬质合金材料的技术领域。本发明的Ti(C,N)基硬质合金材料以TiC粉、TiN<Sub>0.3</Sub>粉和CoCrTiAlSi高熵合金粉为原料,首先压制形成压坯,然后在真空条件下采用热压烧结工艺制备得到；所述TiC、TiN<Sub>0.3</Sub>和CoCrTiAlSi的质量比为26.60～25.20∶68.40～64.80∶5.00～10.00,烧结压力为5～30MPa,烧结温度为1350～1500℃。采用本发明的制备方法得到的Ti(C,N)基硬质合金材料具有较高的强度、硬度和韧性,尤其是中高温耐磨性能良好,适合作为硬质合金刀具材料。(The invention relates to a Ti (C, N) -based hard alloy material and a preparation method thereof, belonging to the technical field of hard alloy materials. The Ti (C, N) -based hard alloy material of the invention is prepared from TiC powder and TiN 0.3 The powder and CoCrTiAlSi high-entropy alloy powder are used as raw materials, firstly pressed to form a pressed compact, and then prepared by adopting a hot-pressing sintering process under a vacuum condition; the TiC and TiN 0.3 The mass ratio of the CoCrTiAlSi to the CoCrTiAlSi is 26.60-25.20: 68.40-64.80: 5.00-10.00, the sintering pressure is 5-30 MPa, and the sintering temperature is 1350-1500 ℃. The Ti (C, N) -based hard alloy material prepared by the preparation method has higher strength, hardness and toughness, particularly has good medium-high temperature wear resistance, and is suitable for being used as a hard alloy cutter material.)

1. A preparation method of Ti (C, N) -based hard alloy is characterized by comprising the following steps: with TiC powder, TiN_0.3The powder and the CoCrTiAlSi high-entropy alloy powder are used as raw materials, firstly pressed to form a pressed compact, and then the powder is prepared by adopting a hot-pressing sintering process under the vacuum condition.

2. The method for producing a Ti (C, N) -based cemented carbide according to claim 1, characterized in that: the TiC and TiN_0.3The mass ratio of the CoCrTiAlSi to the CoCrTiAlSi is 26.60-25.20: 68.40-64.80: 5.00-10.00.

3. The method for producing a Ti (C, N) -based cemented carbide according to claim 1, characterized in that: in the hot-pressing sintering process, the sintering pressure is 5-30 MPa, the sintering temperature is 1350-1500 ℃, and the heat preservation time is 10-30 min.

4. The method for producing a Ti (C, N) -based cemented carbide according to claim 1, characterized in that:the TiN_0.3The powder is prepared by taking Ti powder and urea as raw materials and performing ball milling under the protection of argon.

5. The method for producing a Ti (C, N) -based cemented carbide according to claim 1, characterized in that: the molar ratio of Co, Cr, Ti, Al and Si in the CoCrTiAlSi high-entropy alloy powder is 0.8-1.2: 1.8-2.0: 0.8-1.2.

6. The method for producing a Ti (C, N) -based cemented carbide according to claim 5, characterized in that: the CoCrTiAlSi high-entropy alloy powder is prepared by adopting a gas atomization process.

7. The method for producing a Ti (C, N) -based cemented carbide according to claim 5, characterized in that: the CoCrTiAlSi high-entropy alloy powder contains 0.21-1.56 wt% of nitrogen in total amount.

8. The method for producing a Ti (C, N) -based cemented carbide according to claim 5, characterized in that: the grain size of the CoCrTiAlSi high-entropy alloy powder is less than 74 mu m.

9. The method for producing a Ti (C, N) -based cemented carbide according to claim 1, characterized in that: in the hot-pressing sintering process, the vacuum degree is 1-40 Pa, and the temperature rise speed is 1.0-15 ℃/min.

10. A Ti (C, N) -based cemented carbide produced by the production method according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of hard alloy materials, in particular to a Ti (C, N) -based hard alloy material and a preparation method thereof.

Background

With the continuous development of Ti (C, N) -based cemented carbide in related industrial applications, the requirements for the properties thereof are higher and higher, so it is very important to develop a new Ti (C, N) -based cemented carbide having both high hardness and high toughness. The microstructure of a Ti (C, N) -based cemented carbide consists of a carbonitride (Ti (C, N)) hard phase and a metallic binder phase (Ti, Co, Mo, etc.). The function of the binding phase is to enhance the strength and toughness of the Ti (C, N) -based hard alloy. However, binders such as Co and Ti tend to soften at high temperatures, which results in poor properties of Ti (C, N) -based cemented carbides. The strength and fracture toughness of Co, Ti, etc. bonded Ti (C, N) -based cemented carbides are lower than WC-Co cemented carbides [ Park C, Nam S, Kang S. enhanced toughnessof soft titanium carbide-based ceramics by addition of (Ti, W) C carbides [ J ]. Materials Science & Engineering a, 2016, 649: 400-406.]. Moreover, TiN used for Ti (C, N) -based cemented carbide has high hardness (1950HV), high brittleness and poor toughness, and TiN is very difficult to sinter due to its high melting point (2950 ℃ C.). Therefore, the application and development of Ti (C, N) -based cemented carbide is limited [ Russias J, Cardinal S, Fontaine J, ethyl. bulk titanium material associated from SHS starting powder: densitification, mechanical characterization and structural assessment [ J ]. International Journal of reflective Metals & Hard Materials, 2005, 23 (4-6): 344-349.].

In recent years, high-entropy alloys (HEA) have been widely studied because of their excellent properties. HEA composed of multiple principal elements has a series of characteristics such as high entropy effect, lattice distortion effect, retarded diffusion effect and cocktail effect, so that the HEA has excellent physical, chemical and mechanical properties such as high strength, high hardness, high wear resistance, high corrosion resistance, high low-temperature toughness and the like, and therefore, the problems that the hard alloy is high in hardness and insufficient in toughness, or even if the problems of high hardness and high toughness are met, the HEA cannot realize oxidation resistance or corrosion resistance at high temperature [ Yeh M T j. high-entropy alloys: a critical review [ J ] Materials Research Letters, 2: 3,107-123, 2014.]. Obra et al prepared Ti0.8Ta0.1Nb0.1C0.5N0.5-CoCrFeTiV-C solid solution cermets by a mechanically induced self-sustaining reaction, and after sintering at 1575 ℃ for 60min using a horizontal tube furnace, had hardness and fracture toughness of 10.48GPa and 6.8 MPa.m 1/2[ Obra A G D L, Aviles M A, Torr Y, et al.A new family of cermets: chemical complex build structural simple [ J ]. International Journal of reflective Metals & Hard Materials, 2016, 63: 17-25.]. In addition, in the prior art, hard alloy materials which use high-entropy alloys such as AlCoCrNiFeTi, CoCrTiAlFeMn and the like as metal cohesiveness and use Ti (C, N) as hard phases have been researched, and the materials have high strength and high hardness, but the high-temperature service performance is still poorer than that of the traditional WC-Co-based hard alloy.

Disclosure of Invention

The invention aims to provide a Ti (C, N) -based hard alloy material and a preparation method thereof, aiming at improving the high-temperature service performance of the Ti (C, N) -based hard alloy material.

The invention relates to a preparation method of Ti (C, N) -based hard alloy, which is characterized by comprising the following steps: with TiC powder, TiN_0.3The powder and the CoCrTiAlSi high-entropy alloy powder are used as raw materials, firstly pressed to form a pressed compact, and then the powder is prepared by adopting a hot-pressing sintering process under the vacuum condition.

Wherein, the TiC and TiN_0.3The mass ratio of the CoCrTiAlSi to the CoCrTiAlSi is 26.60-25.20: 68.40-64.80: 5.00-10.00.

Wherein, the sintering pressure in the hot-pressing sintering process is 5-30 MPa, the sintering temperature is 1350-1500 ℃, and the heat preservation time is 10-30 min.

Wherein, the TiN_0.3The powder is prepared from Ti powder and urea (CH)₄N₂O) is prepared by ball milling of raw materials under the protection of argon.

Wherein the molar ratio of Co to Cr to Ti to Al to Si in the CoCrTiAlSi high-entropy alloy powder is 0.8-1.2: 1.8-2.0: 0.8-1.2.

The CoCrTiAlSi high-entropy alloy powder is prepared by adopting a gas atomization process.

Wherein the CoCrTiAlSi high-entropy alloy powder contains 0.21-1.56 wt% of nitrogen in total amount.

Wherein the grain diameter of the CoCrTiAlSi high-entropy alloy powder is less than 74 mu m.

Wherein, the vacuum degree in the hot-pressing sintering process is 1-40 Pa, and the temperature rise speed is 1.0-15 ℃/min.

The second aspect of the present invention also relates to a Ti (C, N) -based cemented carbide produced by the above method.

Compared with the prior art, the Ti (C, N) -based hard alloy material and the preparation method thereof have the following beneficial effects:

the Ti (C, N) -based hard alloy material prepared by the preparation method has higher strength, hardness and toughness, particularly has good medium-high temperature wear resistance, and is suitable for being used as a hard alloy cutter material.

Detailed Description

The Ti (C, N) -based cemented carbide material and the method for manufacturing the same according to the present invention will be further described with reference to the following embodiments to assist those skilled in the art in more complete, accurate and thorough understanding of the technical solution of the present invention.

The invention uses CoCrTiAlSi as the adhesive of Ti (C, N) based hard alloy, and uses TiC and TiN with non-stoichiometric ratio_0.3The novel Ti (C, N) -based hard alloy is prepared by adopting a hot-pressing sintering method for a hard phase, and the raw materials are adopted, so that the sintering temperature is low, the sintering time is short (the temperature rise speed is high), the comprehensive mechanical property is good, and the medium-high temperature wear resistance is excellent.

The composition of the Ti (C, N) -based cemented carbide material of the present invention is shown in table 1.

Table 1 raw materials for preparing novel Ti (C, N) -based cemented carbide and their ratio (wt.%)

In the following examples:

(1) preparation of TiN_0.3The raw materials of the powder are Ti powder (purity is more than 99.36 percent and granularity is less than 30 mu m) and CH₄N₂O (analytically pure). Ti powder and CH₄N₂O is mixed in a molar ratio of 6: 1. In a glove box filled with argon, Ti powder and CH₄N₂O was placed in a WC cemented carbide ball mill jar (150 ml). The mass ratio of the balls to the materials is 20: 1. Three large, medium and small WC hard alloy balls with the diameters of 8mm, 5mm and 2mm respectively are used, and the mass ratio of the large, medium and small WC hard alloy balls is 3: 1. Ball milling is carried out on a planetary ball mill (QM-3SP4 type, China) for 60 hours, the mill is stopped for 30min every 2 hours for heat dissipation, and the rotating speed is set to be 450 r/min.

(2) In examples 1 to 6, CoCrTiAlSi high-entropy alloy powder was prepared by a gas atomization process, in which Co, Cr, Ti, Al and Si were mixed in a molar ratio of 1.0: 2.0: 1.0 to prepare metal raw material powder, which was heated by an induction coil in a melting furnace and vacuum-melted (vacuum degree of 1.0X 10)^-2Pa) melt for controlled meltingThe temperature is 1800 +/-20 ℃, the time is 30min, then a molten metal flow with the diameter of 3mm is formed through a molten liquid outlet, a mixed gas flow of nitrogen and argon is sprayed out through a gas atomization nozzle to impact the molten metal flow, the pressure of the gas flow is 2.0MPa, the nitrogen accounts for 0.5 v% of the mixed gas, spherical CoCrTiAlSi high-entropy alloy powder is obtained after cooling, and the content of the nitrogen in the powder is 0.21 wt% through EDS analysis.