A TiB 2 Modified Mo 2 FeB 2 Preparation method of composite material

Abstract

The invention discloses a TiB 2 Modified Mo 2 FeB 2 The disclosed method comprises: mixing Mo, FeB, Fe and TiB 2 The mixed powder of the powder is ball-milled and molded into a green body in sequence, and then the green body is sintered in a vacuum carbon tube furnace to prepare TiB 2 Modified Mo 2 FeB 2 Based on composite materials; by mass percentage: Mo is 37.0% to 51.0%, FeB is 21.0% to 35.0%, Fe is 12.0% to 31.0%, TiB 2 The present invention uses a small number of raw materials, has a simple preparation process, and a short preparation cycle. The prepared composite material contains Mo 2 FeB 2 Hard phase, Fe-based binder phase and TiB 2 Reinforced phase, with excellent comprehensive mechanical properties.

Description

Technical Field

[0001] The invention relates to Mo2FeB2-based metal ceramic related technologies, belonging to the field of structural functional materials, and specifically to a preparation method of a TiB2-modified Mo2FeB2-based composite material. Background Art

[0002] Ternary boride-based cermets are high-performance cermets prepared using the "reaction boriding sintering principle". The hard phase is not directly added from the raw materials, but is generated by the reaction of the intermediate binary boride and the metal. It has a smooth surface, good wettability with the bonding phase, and high interface bonding strength, which greatly solves the problem of the difficulty in sintering binary borides. Mo2FeB2-based cermets are a typical representative of them. They are composed of Mo2FeB2 hard phase and Fe-based bonding phase, so they have the high hardness, excellent wear resistance and chemical stability of ceramics, and the high strength and good plasticity and toughness of metals. Therefore, Mo2FeB2-based cermets are popular among many researchers.

[0003] The mechanical properties of the Mo2FeB2-based cermets currently prepared are relatively high, which can basically meet the conventional service conditions and can be used to prepare extrusion dies, drawing dies, punching dies, stamping dies, etc. However, with the advancement of science and technology, it is necessary to further improve the comprehensive mechanical properties to meet more severe working conditions. To this end, scientific and technological personnel have adopted many methods to improve the comprehensive mechanical properties of Mo2FeB2-based cermets. In the paper "The Effect of TiC Content on the Organization and Mechanical Properties of Mo2FeB2-based Cermets" in the journal "Powder Metallurgy Industry", Mo powder, FeB powder, Fe powder, TiC powder, Cr powder and Ni powder are used as raw materials, and TiC-enhanced Mo2FeB2-based cermets are made by vacuum sintering, so that the hardness and flexural strength are increased, and the maximum hardness reaches 89.5HRA, and the maximum flexural strength reaches 1660MPa. However, there are many types of raw materials in the prior art, which not only brings difficulty to ensure the consistency of raw material components between batches, but also increases the friction between mixed powders during powder pressing and molding, and needs to add a molding agent (SD-E type) to improve the fluidity of the mixed powder. This requires a special heat preservation program to be set up during sintering to decompose and discharge, which increases the preparation cycle. In addition, due to impurity contamination left in the composite material, the hardness and bending strength of the prepared composite material are insufficient. Summary of the invention

[0004] In view of the defects or shortcomings of the prior art, the present invention provides a method for preparing a TiB2-modified Mo2FeB2-based composite material.

[0005] To this end, the preparation method provided by the present invention comprises: ball milling and compression molding a mixed powder of Mo, FeB, Fe and TiB2 powders in sequence to form a green body, and then sintering the green body in a vacuum carbon tube furnace to prepare a TiB2-modified Mo2FeB2-based composite material;

[0006] In terms of mass percentage: Mo is 37.0% to 51.0%, FeB is 21.0% to 35.0%, Fe is 12.0% to 31.0%, and TiB2 is 2.0% to 10.0%.

[0007] Optionally, the sintering process parameters are: raising the temperature from room temperature to 1250-1350° C. at a heating rate of 5-15° C. / min, and keeping the temperature for 0-50 min, and then cooling the furnace to room temperature.

[0008] Furthermore, the TiB2-modified Mo2FeB2-based composite material contains three phases: a Mo2FeB2 hard phase, a Fe-based bonding phase, and a TiB2 reinforcing phase. The hardness of the TiB2-modified Mo2FeB2-based composite material is 88.6-91.0 HRA, and the flexural strength is 1689.2-2013.6 MPa.

[0009] Compared with the prior art, ① the present invention uses fewer types of raw materials, has a simple preparation process, and a short preparation cycle. The prepared composite material contains a Mo2FeB2 hard phase, an Fe-based bonding phase, and a TiB2 reinforcing phase; ② the composite material prepared in the present invention has excellent comprehensive mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 XRD spectrum of the TiB2-modified Mo2FeB2-based composite material in Example 3 of the present invention;

[0011] Figure 2 This is a microstructure photograph of the TiB2-modified Mo2FeB2-based composite material in Example 3 of the present invention. DETAILED DESCRIPTION

[0012] Unless otherwise specified, the scientific and technological terms and methods herein are understood according to the knowledge of ordinary technicians in the relevant field or implemented using existing relevant methods. It should also be understood that the temperature and insulation time involved in this article are approximate values ​​for illustrative purposes. Although methods and materials similar or equivalent to the methods and materials described herein can be used for the implementation of the present disclosure, some suitable methods and materials are described below. The publications, patent applications, patents and other references mentioned herein are partially incorporated herein by reference. In the event of a conflict, this article shall prevail. In addition, the materials, methods, material ratios and embodiments are merely exemplary and are not intended to be limiting. In a specific scheme, those skilled in the art can optimize the material ratios and operating parameter values ​​involved in the method according to the disclosure of the present invention using conventional experimental time periods to achieve the purpose of the present invention.

[0013] The purpose of the compression molding of the present invention is to make the powdered raw material preliminarily dense, and the shape and size of the obtained green body depends on the shape of the mold. Existing molds used in the ceramic field, such as molds with a volume size greater than 3mm*3mm, are suitable for the present invention.

[0014] In the process of the present invention, sintering is carried out in a vacuum carbon tube furnace. Based on the disclosure of the present invention, those skilled in the art can use conventional experimental means to optimize the specific sintering for different formula materials and the effects of the present invention. The specific sintering process adopted in the following embodiments is only a specific example to explain the scheme of the present invention, and the sintering process of the present invention is not limited thereto. The sintering process conditions are exemplified by raising the temperature from room temperature to 1250-1350°C at a heating rate of 5-15°C / min, and keeping the temperature for 0-50min, and then cooling the furnace to room temperature.

[0015] The present invention is further described in detail by examples. The raw materials Mo, Fe, B and TiB2 powder used in the examples of the present invention are all commercially available chemically pure powder reagents; the ball milling adopts a planetary ball mill (QM-3SP4). However, the present invention is not limited to these specific equipments.

[0016] In the present invention, a HRS-150 Rockwell hardness tester is used to measure the hardness of the TiB2 modified Mo2FeB2 based composite material; referring to the national standard GB / T6569-2006, a three-point bending test method is used to test the flexural strength of the TiB2 modified Mo2FeB2 based composite material sample.

[0017] Embodiment 1:

[0018] In this embodiment, Mo, FeB, Fe and TiB2 powders with a purity of not less than 99.0% are selected as raw materials, and the mass percentages are: Mo is 51.0%, FeB is 35.0%, Fe is 12.0%, and TiB2 is 2.0%;

[0019] The mixed powder is ball-milled and pressed into a cylindrical body (diameter 44 mm, height 8-9 mm);

[0020] The green body was then placed in a vacuum carbon tube furnace for sintering. The sintering process parameters were: the temperature was raised from room temperature to 1250°C at a heating rate of 5°C / min, and kept at that temperature for 0 min, and then the furnace was cooled to room temperature.

[0021] The TiB2-modified Mo2FeB2-based composite material prepared in this embodiment comprises a Mo2FeB2 hard phase, an Fe-based bonding phase and a TiB2 reinforcing phase, and has a hardness of 88.6HRA and a flexural strength of 1689.2MPa.

[0022] Embodiment 2:

[0023] In this embodiment, Mo, FeB, Fe and TiB2 powders with a purity of not less than 99.0% are selected as raw materials, and the mass percentages are: Mo is 44.0%, FeB is 28.0%, Fe is 22.0%, and TiB2 is 6.0%;

[0024] The mixed powder is ball-milled and pressed into a cylindrical body (diameter 44 mm, height 8-9 mm);

[0025] The green body was then placed in a vacuum carbon tube furnace for sintering. The sintering process parameters were: the temperature was raised from room temperature to 1300°C at a heating rate of 10°C / min, and kept at that temperature for 25 minutes, and then the furnace was cooled to room temperature.

[0026] The TiB2-modified Mo2FeB2-based composite material prepared in this embodiment comprises a Mo2FeB2 hard phase, an Fe-based bonding phase and a TiB2 reinforcing phase, and has a hardness of 89.9 HRA and a flexural strength of 1847.2 MPa.

[0027] Embodiment 3:

[0028] In this embodiment, Mo, FeB, Fe and TiB2 powders with a purity of not less than 99.0% are selected as raw materials, and the mass percentages are: Mo is 37.0%, FeB is 22.0%, Fe is 31.0%, and TiB2 is 10.0%;

[0029] The mixed powder is ball-milled and pressed into a cylindrical body (diameter 44 mm, height 8-9 mm);

[0030] The green body was then placed in a vacuum carbon tube furnace for sintering. The sintering process parameters were: the temperature was raised from room temperature to 1350°C at a heating rate of 15°C / min, and kept at that temperature for 50 minutes, and then the furnace was cooled to room temperature.

[0031] The TiB2-modified Mo2FeB2-based composite material prepared in this embodiment comprises a Mo2FeB2 hard phase, a Fe-based bonding phase and a TiB2 reinforcement phase (see XRD pattern). Figure 1 ), microstructure see Figure 2 ; The hardness of the composite material is 91.0HRA and the flexural strength is 2013.6MPa.

[0032] Comparative Example:

[0033] This comparative example is different from Example 3 in that the raw material does not contain TiB2 powder.

[0034] The Mo2FeB2-based composite material obtained in this comparative example comprises a Mo2FeB2 hard phase and a Fe-based bonding phase, and has a hardness of 87.3HRA and a flexural strength of 1446.8MPa.

[0035] The test properties of the composite materials of the above embodiments and comparative examples are shown in Table 1.

[0036] Table 1 Mechanical properties of composite materials

[0037] sample Hardness / HRA Bending strength / MPa Comparative Example 87.3 1446.8 Example 1 88.6 1689.2 Example 2 89.9 1847.2 Example 3 91.0 2013.6

[0038] It can be seen from the test results in Table 1 that compared with the comparative example, the hardness and flexural strength of the TiB2-modified Mo2FeB2-based composite material prepared by the present invention are increased, with the maximum hardness reaching 91.0HRA, an increase of about 3.7HRA, and the maximum flexural strength increasing by about 39.2%, and the comprehensive mechanical properties are significantly improved.

Claims

1. A method for preparing a TiB2-modified Mo2FeB2-based composite material, characterized in that: The method comprises: ball milling and compression molding a mixed powder of Mo, FeB, Fe and TiB2 powders in sequence to form a green body, and then sintering the green body in a vacuum carbon tube furnace to prepare a TiB2-modified Mo2FeB2-based composite material; By mass percentage: Mo is 37.0% to 51.0%, FeB is 21.0% to 35.0%, Fe is 12.0% to 31.0%, and TiB2 is 2.0% to 10.0%; The hardness of the TiB2-modified Mo2FeB2-based composite material is 88.6-91.0 HRA, and the flexural strength is 1689.2-2013.6 MPa.

2. The method for preparing the TiB2-modified Mo2FeB2-based composite material according to claim 1, characterized in that: The sintering process parameters are as follows: the temperature is raised from room temperature to 1250-1350°C at a heating rate of 5-15°C / min, and kept at that temperature for 0-50min, and then the furnace is cooled to room temperature.

3. The method for preparing the TiB2-modified Mo2FeB2-based composite material according to claim 1, characterized in that: The TiB2 modified Mo2FeB2 based composite material comprises three phases: a Mo2FeB2 hard phase, a Fe based bonding phase and a TiB2 reinforcing phase.

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