阅读说明：本技术 一种碳化钨铝-碳化钛硬质材料的制备方法 (Preparation method of tungsten aluminum carbide-titanium carbide hard material ) 是由 刘建伟 马贤锋 汤华国 赵伟 于 2020-08-07 设计创作，主要内容包括：本发明提供了一种碳化钨铝-碳化钛硬质材料的制备方法,包括以下步骤：A)将钨铝合金粉、钛粉和碳粉混合,球磨3～5h,得到混合粉体；B)将所述混合粉体在成型剂和防锻剂中再次混料后冷压成型,得到坯体；C)将所述坯体进行真空热压烧结,得到碳化钨铝-碳化钛硬质材料。本发明提供了无粘结相型碳化钨铝-碳化钛硬质材料的制备方法,具体涉及以钨铝合金粉、钛粉、碳粉为原料,通过高能球磨和反应烧结的方式制备无粘结相型碳化钨铝-碳化钛硬质材料。(The invention provides a preparation method of a tungsten carbide aluminum-titanium carbide hard material, which comprises the following steps: A) mixing tungsten-aluminum alloy powder, titanium powder and carbon powder, and performing ball milling for 3-5 hours to obtain mixed powder; B) mixing the mixed powder in a forming agent and a forging inhibitor again, and then carrying out cold press forming to obtain a blank body; C) and carrying out vacuum hot-pressing sintering on the blank to obtain the tungsten carbide aluminum-titanium carbide hard material. The invention provides a preparation method of a non-bonding phase type tungsten aluminum carbide-titanium carbide hard material, and particularly relates to a method for preparing a non-bonding phase type tungsten aluminum carbide-titanium carbide hard material by taking tungsten aluminum alloy powder, titanium powder and carbon powder as raw materials and adopting a high-energy ball milling and reaction sintering mode.)

1. A preparation method of a tungsten carbide aluminum-titanium carbide hard material comprises the following steps:

A) mixing tungsten-aluminum alloy powder, titanium powder and carbon powder, and performing ball milling for 3-5 hours to obtain mixed powder;

B) mixing the mixed powder in a forming agent and a forging inhibitor again, and then carrying out cold press forming to obtain a blank body;

C) and carrying out vacuum hot-pressing sintering on the blank to obtain the tungsten carbide aluminum-titanium carbide hard material.

2. The preparation method according to claim 1, wherein the mass ratio of the tungsten-aluminum alloy powder to the carbon powder to the titanium powder is (20-120): (1-8): 1.

3. the preparation method according to claim 1, wherein the particle size of the tungsten-aluminum alloy powder is less than 0.8 μm, and the purity is more than 99.7%; the mesh number of the titanium powder is 200 meshes, and the purity is more than 99.5 percent; the mesh number of the carbon powder is 200 meshes, and the purity is more than 99 percent.

4. The preparation method of claim 1, wherein the ball-milling has a ball-to-material ratio of (3-6): 1, the granularity of the mixed powder is 0-100 nm.

5. The preparation method of claim 1, wherein in the step A), a forging inhibitor is added in the ball milling, the forging inhibitor is ethanol, and the amount of the forging inhibitor is 0.01-0.05 ml/g.

6. The preparation method of claim 1, wherein in the step B), the forming agent is paraffin, the anti-forging agent is ethanol, and the mixing time is 15-30 min.

7. The preparation method according to claim 1, wherein in the step B), the pressure of cold press forming is 150-250 MPa.

8. The preparation method according to claim 1, wherein in the step C), the temperature of the vacuum hot-pressing sintering is 1100-1500 ℃ and the time is 1-10 min.

9. The method according to claim 1, wherein in step C), the initial pressure of the vacuum hot-pressing sintering is 10 to 30MPa, and the pressurizing pressure is 80 to 120 MPa.

10. The preparation method according to claim 1, wherein in the step C), the vacuum hot-pressing sintering process is specifically as follows:

and placing the blank body in a mold, initially pressurizing to 10-30 MPa, rapidly heating to 1100-1300 ℃, pressurizing to 80-120 MPa, and preserving heat for 1-10 min.

Technical Field

The invention relates to the technical field of hard materials, in particular to a preparation method of a tungsten carbide aluminum-titanium carbide hard material.

Background

Tungsten is a scarce and non-renewable important strategic resource, which is expensive and has limited resources. The efficient utilization of tungsten resources has important significance for the development of related industries. The aluminum partially replaces tungsten, so that consumption of tungsten resources is saved, and the performance of the material is improved.

Conventional cemented carbides consist of two parts, a hard phase (tungsten carbide, titanium carbide, etc.) and a binder phase (cobalt, nickel, iron, etc.). The conventional hard alloy is prepared by adding a binding phase and utilizing a powder metallurgy sintering method. However, for carbides without binding phase, because the melting point is very high, the general powder metallurgy method is difficult to sinter, and the tungsten carbide material is difficult to realize compact sintering without binding metal, so that the material strength and toughness are low; however, as the binder metal is added, the strength of the material increases, but the hardness thereof is greatly reduced. How to solve the contradiction becomes a difficult problem for preparing hard materials.

The tungsten aluminum carbide material is a novel hard material developed in recent years, and is a substitutional solid solution formed by partially replacing tungsten atoms with aluminum atoms. Compared with tungsten carbide, the material has more excellent mechanical property, and is expected to be applied to the fields of machining tools, dies, drilling tools and the like.

Disclosure of Invention

The invention aims to provide a method for preparing a tungsten aluminum carbide-titanium carbide hard material, which can be used for preparing the tungsten aluminum carbide-titanium carbide hard material by rapid reaction sintering at a lower temperature, and the hard material has higher hardness and strength.

The application provides a preparation method of a tungsten carbide aluminum-titanium carbide hard material, which comprises the following steps:

A) mixing tungsten-aluminum alloy powder, titanium powder and carbon powder, and performing ball milling for 3-5 hours to obtain mixed powder;

B) mixing the mixed powder in a forming agent and a forging inhibitor again, and then carrying out cold press forming to obtain a blank body;

C) and carrying out vacuum hot-pressing sintering on the blank to obtain the tungsten carbide aluminum-titanium carbide hard material.

Preferably, the mass ratio of the tungsten-aluminum alloy powder to the carbon powder to the titanium powder is (20-120): (1-8): 1.

preferably, the particle size of the tungsten-aluminum alloy powder is less than 0.8 μm, and the purity is more than 99.7%; the mesh number of the titanium powder is 200 meshes, and the purity is more than 99.5 percent; the mesh number of the carbon powder is 200 meshes, and the purity is more than 99 percent.

Preferably, the ball-milling ball-material ratio is (3-6): 1, the granularity of the mixed powder is 0-100 nm.

Preferably, in the step A), a forging inhibitor is added in the ball milling, the forging inhibitor is ethanol, and the using amount of the forging inhibitor is 0.01-0.05 ml/g.

Preferably, in the step B), the forming agent is paraffin, the anti-forging agent is ethanol, and the mixing time is 15-30 min.

Preferably, in the step B), the pressure of the cold press molding is 150-250 MPa.

Preferably, in the step C), the temperature of the vacuum hot-pressing sintering is 1100-1500 ℃, and the time is 1-10 min.

Preferably, in the step C), the initial pressure of the vacuum hot-pressing sintering is 10-30 MPa, and the pressurizing pressure is 80-120 MPa.

Preferably, in the step C), the vacuum hot-pressing sintering process specifically includes:

and placing the blank body in a mold, initially pressurizing to 10-30 MPa, rapidly heating to 1100-1300 ℃, pressurizing to 80-120 MPa, and preserving heat for 1-10 min.

The application provides a preparation method of a tungsten aluminum carbide-titanium carbide hard material, which takes tungsten aluminum alloy powder, titanium powder and carbon powder as raw materials, prepares nano-scale mixed powder by high-energy ball milling, utilizes the reaction of the tungsten aluminum alloy and carbon, titanium and carbon to release heat, particularly the reaction of titanium and carbon, and is beneficial to inducing and promoting the sintering process, reducing the sintering temperature, shortening the sintering time and inhibiting the growth process of crystal grains; meanwhile, the characteristics of high sintering speed, low sintering temperature and the like of the nano powder are combined, so that the rapid reaction sintering at a lower temperature can be realized; the hot-pressing sintering is adopted in the sintering process of the nano powder and certain stress is assisted, so that the aggregation, combination and coarsening speed of crystal grains is high, the combination and growth speed of pores is high, the reaction and sintering process is accelerated, the density is improved, the growth of the crystal grains is inhibited, and the low-temperature rapid densification sintering of the material is favorable for improving the performance of the material; on one hand, the mechanical properties such as hardness, strength and the like of the material can be simultaneously improved by refining the microstructure, and on the other hand, the titanium carbide in-situ reinforced tungsten aluminum carbide further improves various mechanical properties, particularly the strength, of the material.

Drawings

FIG. 1 is an XRD pattern of a tungsten aluminum carbide-titanium carbide hard material prepared in example 1 of the present invention.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

In view of the problem that densification sintering difficulty is high in the case that tungsten aluminum carbide does not have a binder in the prior art, the application provides a preparation method of a tungsten aluminum carbide-titanium carbide hard material. Specifically, the embodiment of the invention discloses a preparation method of a tungsten carbide aluminum-titanium carbide hard material, which comprises the following steps:

A) mixing tungsten-aluminum alloy powder, titanium powder and carbon powder, and performing ball milling for 3-5 hours to obtain mixed powder;

B) mixing the mixed powder in a forming agent and a forging inhibitor again, and then carrying out cold press forming to obtain a blank body;

C) and carrying out vacuum hot-pressing sintering on the blank to obtain the tungsten carbide aluminum-titanium carbide hard material.

In the preparation process of preparing the tungsten carbide aluminum-titanium carbide hard material, firstly, mixing tungsten-aluminum alloy powder, titanium powder and carbon powder, and carrying out ball milling for 3-5 hours to obtain mixed powder; in the process, the tungsten-aluminum alloy powder is less than 0.8 μm and the purity is more than 99.7%; commercial titanium powder, 200 mesh, purity greater than 99.5%; commercial carbon powder (graphite powder), 200 mesh, purity greater than 99%. The mass ratio of the tungsten-aluminum alloy powder to the carbon powder to the titanium powder is (20-120): (1-8): 1; more specifically, the mass ratio of the tungsten-aluminum alloy powder to the carbon powder to the titanium powder is (35-40): (1.5-4.5): 1. after the raw materials are prepared, ball milling is performed, in the present application, the ball milling is specifically high-energy ball milling, specifically, the raw materials are put into a ball milling tank under the protection of argon gas, and the used equipment is a planetary ball mill, which is not particularly limited, and can be high-energy ball milling equipment well known to those skilled in the art. The powder granularity has no special requirements, the larger the initial powder granularity is, the ball milling parameters are slightly adjusted, but the final size of the ball milling powder crystal grains is not influenced. In the ball milling process, the ball-to-material ratio of the ball milling is (3-6): 1, in a specific embodiment, the ball-milling ratio of balls to materials is 4:1 and 5: 1; the ball milling time is 3-5 hours, more preferably 4 hours, the ball milling time is long, titanium carbide is generated in the ball milling process of titanium powder and carbon powder, the later-stage reaction sintering is not facilitated, the ball milling time is too short, the granularity of the tungsten-aluminum alloy powder is large, and the sintering and the performance improvement are not facilitated. In the process of ball milling, ethanol is selected as the anti-forging agent, the dosage is 0.01 ml/g-0.05 ml/g, preferably 0.02ml/g, the efficiency is influenced too much, and the powder is less agglomerated. The granularity of the mixed powder after ball milling is controlled to be 0-100 nm, and more preferably 10-20 nm. In the ball milling process, the particle size of the powder is reduced along with the ball milling, the activity of the powder is increased, the tungsten-aluminum alloy can react with carbon to generate tungsten aluminum carbide after a certain ball milling time is exceeded, titanium can react with carbon to generate titanium carbide, particularly, the titanium can react with the carbon more easily, the ball milling time is relatively short, and in order to control the reaction process to be carried out in the sintering process instead of the ball milling process, the ball milling time is controlled.

The obtained mixed powder is mixed again in a forming agent and a forging inhibitor and then is subjected to cold press forming, and a blank body is obtained; in the process, the forming agent is paraffin, the anti-forging agent is ethanol, and the re-mixing is specifically a three-dimensional mixing material so as to realize uniform mixing of the mixed powder. After mixing, taking out, drying in vacuum and then carrying out cold press molding; the cold press forming is a technical means well known to those skilled in the art, and there is no particular limitation to this application; the pressure of the cold press molding is 150-250 MPa, and more specifically, the pressure of the cold press molding is 180-220 MPa. In the process, the higher the density of the cold press forming is, the more favorable the later sintering is.

And finally, carrying out vacuum hot-pressing sintering on the obtained blank to obtain the tungsten carbide aluminum-titanium carbide hard material. In the process, the reaction of carbon and titanium in the ball milling process is beneficial to reducing the sintering temperature and shortening the sintering time; meanwhile, the prepared nano-scale mixed powder is also beneficial to improving the sintering rate and reducing the sintering temperature, and finally, the rapid reaction sintering at a lower temperature is realized. The rapid reaction sintering of the application inhibits the growth of crystal grains, so that the crystal grains are refined, and meanwhile, the strength, the hardness and the toughness of the material are further enhanced due to the fact that the titanium carbide in situ reinforces the tungsten aluminum carbide.

The temperature of the vacuum hot-pressing sintering is preferably 1100-1500 ℃, and more preferably 1400-1500 ℃; the sintering time is preferably 1 to 10 minutes, and more preferably 3 to 5 minutes. The vacuum hot-pressing sintering process comprises the following specific steps: and placing the blank body in a mold, initially pressurizing to 10-30 MPa, rapidly heating to 1100-1300 ℃, pressurizing to 80-120 MPa, and preserving heat for 1-10 min. The titanium content, the sintering temperature and the sintering time have a mutual coupling relation, the sintering temperature is reduced along with the increase of the titanium content, and the sintering time is reduced along with the increase of the sintering temperature; the sintering temperature is too high, the crystal grains grow rapidly, the abnormal growth of the crystal grains is increased, the hardness of the material is slightly reduced, and the strength is obviously reduced; the sintering temperature is reduced, and the sintering time is prolonged. The sintering time is too short, the reaction is not completely carried out, the porosity is increased, and the hardness and the strength are reduced. Therefore, the titanium carbide dispersion-strengthened non-binding phase tungsten carbide aluminum with excellent performances such as hardness, strength and the like can be obtained only by completing the reaction of the material and the sintering process of the material and optimizing and coupling the titanium content, the sintering temperature and the sintering time.

For further understanding of the present invention, the following examples are provided to illustrate the preparation method of the aluminum tungsten carbide-titanium carbide hard material, and the scope of the present invention is not limited by the following examples.

The tungsten aluminum carbide-titanium carbide hard material without the bonding phase prepared by the invention is tested for hardness by referring to the national standard GB/T7997-2014 hard alloy Vickers hardness test method; the strength of the hard alloy is tested by using an INSTRON-5869 type material testing machine according to the national standard GB/T3851-2015 hard alloy transverse rupture strength measuring method.