KR20150002162A - Manufacturing method of titanium alloy using self propagating high-temperature synthesis - Google Patents

Abstract

The present invention relates to a method of manufacturing a Ti alloy using self-propagating high-temperature synthesis. And more specifically, the method of manufacturing the Ti alloy of the Ti-Al-V group using the self-propagating high temperature synthesis capable of reacting in the fast time by own reaction heat and having a simple facility and process. The method of manufacturing the Ti alloy using the self-propagating high-temperature synthesis of the present invention comprises: a combustion step of mixing oxide titanium, aluminum, oxide vanadium, and a reducing agent and self-propagating the mixture; and a post processing step of removing an oxide of the combustion product obtained from the combustion step and obtaining the Ti-Al-V group alloy.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a titanium alloy using a self-propagating high-

More particularly, the present invention relates to a method for producing a Ti-Al-V alloy using a self-sustaining combustion reaction, which can be quickly reacted by its own reaction heat, Titanium alloy. ≪ Desc / Clms Page number 2 >

Titanium alloys are used in a variety of industrial fields such as aerospace, marine, sports, and medical applications due to their high nasal strength, excellent corrosion resistance and biocompatibility.

Pure titanium is transformed into a β-phase having a body-centered cubic structure by an isotropic transformation at a temperature of 882 ° C. at an α-phase having a dense hexahedral structure at room temperature. When alloying elements are added to pure titanium, a region in which α and β phases coexist in a certain temperature range exists, and in some cases, this region extends to room temperature.

Titanium alloys are generally classified as α alloys, β alloys, and α + β alloys. The most widely used alloys are α + β alloys, which are composed of molybdenum (Mo), iron (Fe), vanadium (V), and boron , Chromium (Cr), and neutral elements such as zirconium (Zr) and tin (Sn).

Among the α + β alloys, the most representative titanium alloys are Ti-Al-V alloys such as Ti-6Al-4V, Ti-9Al-6V and Ti-12Al-8V. Ti-Al-V alloys account for more than 60% of total titanium alloy use because they have excellent hot workability and weldability and various mechanical properties are obtained by heat treatment.

In particular, the Ti-6Al-4V alloy is a representative titanium alloy having excellent non-strength (strength / density) at a temperature ranging from room temperature to 400 ° C and excellent mechanical properties such as toughness and elongation, And so on.

A conventional method for producing a Ti-Al-V alloy is disclosed in Korean Patent Publication No. 2012-0065780. In the above-mentioned patents, an alloy ingot was prepared by mixing 6 wt% aluminum, 4 wt% vanadium, and 90 wt% titanium and then dissolving, and then hot-working the ingot to prepare an alloy.

The conventional method for producing the Ti-Al-V alloy has a problem in that the equipment and the process are complicated and energy is consumed because the alloy is manufactured by dissolving the metal materials by applying heat at a high temperature.

The present invention has been made in order to overcome the above problems, and it is an object of the present invention to provide a Ti-Al-V The present invention also provides a method for producing a titanium alloy of the above-mentioned type.

In order to accomplish the above object, the present invention provides a method of manufacturing a titanium alloy using a self-sustaining combustion reaction, comprising: a combustion step of mixing a mixture obtained by mixing titanium oxide, aluminum, vanadium oxide and a reducing agent; And a post-treatment step of removing the oxide from the combustion products obtained in the combustion step to obtain a Ti-Al-V alloy.

Wherein the combustion step comprises the steps of: a) filling the reaction vessel with the mixture; b) mounting the reaction vessel in a chamber of a self-combustion reactor; c) supplying power to the ignition coil installed in the chamber, And a step of burning.

And injecting argon gas into the chamber, followed by combustion of the mixture.

Wherein the post-treatment step comprises the steps of: a) grinding the combustion product; b) adding an acid solution to the comminuted combustion product to separate the precipitate and the leach solution after leaching the oxide; c) And drying it.

And the reducing agent in the combustion step is magnesium.

And the molar ratio of the titanium oxide: the aluminum: the vanadium oxide: the reducing agent is 1.875: 0.22: 0.04: 4.7.

As described above, according to the present invention, the titanium alloy is manufactured by using the self-reaction heat, which can be reacted quickly by its own reaction heat, without supplying any additional energy, so that the manufacturing facility and process can be simplified and the energy consumption can be greatly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a rotating combustion reactor applied to the present invention,
Figure 2 is the XRD pattern result of the titanium alloy prepared in the example,
FIGS. 3 and 4 are scanning electron microscope (SEM) photographs of titanium alloys prepared in Examples. FIG.

Hereinafter, with reference to the accompanying drawings, a method of manufacturing a titanium alloy using a spin-reaction according to a preferred embodiment of the present invention will be described in detail.

The present invention produces a titanium alloy using a self-sustaining combustion reaction that is simple in equipment and process and can be reacted quickly by its own reaction heat without supplying any additional energy.

The self-propagating high-temperature synthesis (SHS), which is applied to the present invention, uses a solid-solid chemical reaction as an exothermic reaction, and utilizes its own heat of chemical reaction It means synthesizing the material.

Such a self-combustion reaction does not require a high-temperature reaction furnace, and the production process is simple. Since titanium dioxide is synthesized in a short time, it is expected that energy consumption is very small and productivity is high.

An example of a conventional rotating combustion reactor for carrying out a rotary combustion reaction is shown in Fig.

Referring to FIG. 1, the rotating combustion reactor includes a chamber 20 for charging and reacting the reaction vessel 10, an ignition coil 30 disposed in the chamber 20 for initiating a self-ignition reaction, A gas supply pipe 51 for supplying an inert gas into the chamber 20 and a gas discharge pipe 55 for discharging the gas. The gas supply pipe 51 is connected to a gas storage tank (not shown) in which the gas is stored. The gas discharge pipe 55 may be provided with a pump and a gauge to control the pressure inside the chamber 20. And a vacuum hose 60 for creating a vacuum in the chamber 20 is connected to the lower portion of the chamber 20. The vacuum hose 60 is connected to a vacuum pump (not shown) located outside the chamber 20. The vacuum pump draws air out of the chamber 20 to create a vacuum.

The ignition coil 30 may be in the form of a coil of nickel (Ni) - chromium (Cr). The outer wall of the chamber 20 is preferably made of a ceramic material such as graphite, which is resistant to high temperature for preventing heat loss and for heat insulation.

The method of manufacturing a titanium alloy according to an embodiment of the present invention largely includes a combustion step and a post-processing step. Each step will be examined in detail.

1. Combustion stage

In the combustion step, the reducing agent is mixed with the metals, which are the material of the alloy, and then the combustion product is obtained by rotating the mixture.

B) filling the reaction vessel in a chamber of a combustion combustion reactor; c) contacting the mixture mounted in the chamber with an ignition coil, And combusting the mixture.

First, a mixture is obtained by mixing a reducing agent and metals serving as an alloy material. Titanium oxide, aluminum and vanadium oxide are used as metals for the alloy. TiO ₂ as titanium oxide and V ₂ O ₅ as vanadium oxide can be used.

And magnesium can be used as a reducing agent. In burning, oxygen is lost from titanium oxide and vanadium oxide and reduced, and magnesium is oxidized to oxide (MgO) in combination with oxygen.

Titanium oxide, aluminum, vanadium oxide and reducing agent are mixed at an appropriate molar ratio depending on the type of alloy titanium to be produced. For example, when a Ti-6Al-4V alloy is to be prepared, it is preferable to mix it at a molar ratio of 1.875: 0.22: 0.04: 4.7. That is, the molar ratio of TiO ₂ : Al: V ₂ O ₅ : Mg is 1.875: 0.22: 0.04: 4.7.

The titanium oxide, aluminum, vanadium oxide and reducing agent are preferably used in the form of chips or powders. When used in powder form, the particle size of each metal is 0.1 to 100 탆.

When a mixture of titanium oxide, aluminum, vanadium oxide, and a reducing agent is prepared, the mixture is filled in the reaction vessel 10. The mixture is placed in a reaction vessel, and the mixture is compressed by applying a constant pressure.

After charging the mixture into the reaction vessel, the reaction vessel is mounted inside the chamber of the rotating combustion reactor. In the mounting step, the reaction vessel is placed so that the ignition coil 30 is brought into contact with the upper part of the mixture or separated by about 1 to 3 mm.

Next, the chamber door is closed and a vacuum pump is operated to form a vacuum atmosphere in the chamber 102, and then argon gas is injected into the chamber with an inert gas. At this time, argon gas is injected until the pressure in the chamber reaches 2 to 3 MPa. By injecting argon gas in this way, the pressure inside the chamber can be kept constant, thereby preventing scattering of the metal powder during combustion.

After injecting argon gas, power is supplied to the ignition coil to heat the ignition coil. When the ignition coil 30 is heated to raise the temperature to the reaction initiation temperature of 600 to 1000 占 폚, the mixture is ignited to start combustion of the mixture, and the reaction is continued until the reaction is completed by the heat of reaction formation.

By the combustion reaction, titanium oxide and vanadium oxide lose oxygen and are reduced to produce a titanium alloy of Ti-Al-V system. Magnesium as a reducing agent is oxidized to magnesium oxide by binding with oxygen.

After the combustion reaction, the temperature of the chamber is cooled to room temperature, and the lumpy combustion products are separated in the reaction vessel. Some unburnt metal may be present on the sides and top and bottom of the combustion products. In this case, the surface of the combustion product is scraped off to remove unburned metal.

2. Post-processing step

Since the combustion products obtained in the combustion step contain magnesium oxide (MgO), a post-treatment step for removing the magnesium oxide is performed.

An example of a post-treatment step comprises the steps of: a) crushing a combustion product; b) adding an acid solution to the comminuted combustion product to separate the leach solution and precipitate after leaching the oxide; c) .

The combustion products are pulverized to an appropriate size to be obtained. It may be pulverized using a conventional mortar or a pulverizer.

Next, an acid solution is added to the pulverized combustion products to leach out the magnesium oxide contained in the combustion products. A nitric acid solution can be used as the acid solution. A solution diluted to about 5 to 50% with a nitric acid solution may be used. The combustion products and acid solutions are allowed to react for 0.5 to 5 hours at a temperature of about 50-70 ° C. The magnesium oxide is dissolved in nitric acid, and the solid Ti-Al-V alloy precipitates at the bottom of the leach solution to form a precipitate. The reaction of the nitric acid solution with the combustion products is as follows.

Ti-Al-V + 2MgO + HNO 3 (l) → Ti-Al-V ↓ + (2MgO + HNO ₃ ) (l)

After the magnesium oxide is leached, solid-liquid separation is carried out to separate the leach solution and the precipitate. Various methods can be applied by the solid-liquid separation method. A filtering method using a filter paper, a separation method based on a difference in specific gravity, a separation method using centrifugation, and the like can be applied.

After separating the precipitate from the leach solution, the precipitate is washed and dried. Wash the precipitate repeatedly with distilled water several times until it becomes neutral. After washing, the Ti-Al-V alloy can be obtained by drying at 60 to 80 ° C in an oven.

Examples of the Ti-Al-V alloy manufactured using the above-described manufacturing method include Ti-6Al-4V, Ti-9Al-6V, and Ti-12Al-8V.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples serve to illustrate the present invention, and the scope of the present invention is not limited thereto.

(Example)

TiO ₂ Powder (PC-500, MILLENIUM, Korea), Al powder (Alfa Aesar, UK), V ₂ O ₅ (TiO ₂ : Al: V ₂ O ₅ : Mg) were mixed at a molar ratio of 1.875: 0.22: 0.04: 4.7. Then, the mixture was placed in a reaction vessel having a diameter of 6 cm and a height of 12 cm, and then pressed to fill the reaction vessel.

Then, the reaction vessel was mounted in a chamber of a self-assembled rotary combustion reactor, and then a vacuum pump was operated to form a vacuum chamber. Then, argon gas was introduced into the chamber to maintain the pressure of the chamber at about 2.5 MPa. Then, power was supplied to the ignition coil to rotate the mixture, and after cooling, the combustion products were separated from the reaction vessel. The surface was scratched to remove unburned matter and then pulverized to a size of about 300 mu m.

The pulverized combustion product was put into a 30% nitric acid solution and magnesium oxide was leached for 1 hour, and then a solid precipitate was obtained using a filter paper. The precipitate was washed three times with distilled water and dried at 70 ° C in a vacuum oven to prepare a Ti-Al-V-based titanium alloy.

The XRD pattern was measured to confirm the titanium alloy prepared in the above example, and the results are shown in FIG. FIG. 2 shows that the titanium alloy prepared in the examples is Ti-6Al-4V.

SEM photographs of the titanium alloys prepared in the above examples are shown in FIGS. 3 and 4. FIG.

Referring to FIGS. 3 and 4, it can be seen that the titanium alloy is formed into a porous structure. This is because the magnesium oxide is leached through the post-treatment process and the removed portion remains as pores.

The results of analysis by EDX (Energy Dispersive X-ray Spectroscopy) of the titanium alloy produced in the above Examples are shown in Table 1 below.

element weight (% by weight) Al 6.17 Ti 90.02 V 3.81 Total 100.00

Referring to the results of Table 1, it can be seen that the main component of the alloy is Ti, and that small amounts of Al and V are contained. As a result, Ti-Al-V alloy was formed. Mg and O were not detected, indicating that magnesium oxide was well removed in the post-treatment.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

10: reaction vessel 20: chamber
30: Ignition coil 40: Power supply
51: gas supply pipe 55: gas discharge pipe
60: Vacuum hose

Claims (6)

A burning step of burning the mixture obtained by mixing titanium oxide, aluminum, vanadium oxide and a reducing agent;
And a post-treatment step of removing the oxides from the combustion products obtained in the combustion step to obtain a Ti-Al-V based alloy. The method of claim 1, wherein the combustion step comprises the steps of: a) filling the reaction vessel with the mixture; b) mounting the reaction vessel in a chamber of a self-combustion reactor; c) And then burning the mixture. The method of manufacturing a titanium alloy according to claim 1, 3. The method of claim 2, wherein argon gas is injected into the chamber and then the mixture is burned. The method of claim 1, wherein the post-treatment step comprises the steps of: a) grinding the combustion product; b) adding an acid solution to the pulverized combustion product to leach the oxide and then separating the leach solution and precipitate; c ) Washing the precipitate and drying the titanium alloy. The method of manufacturing a titanium alloy according to claim 1, wherein the reducing agent in the combustion step is magnesium. 6. The method of claim 5, wherein the molar ratio of the titanium oxide: the aluminum: the vanadium oxide: the reducing agent is 1.875: 0.22: 0.04: 4.7.

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